1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
ANEK [815]
3 years ago
13

A chemist has two alloys, one of which is 15% gold and 20% lead and the other which is 30% gold and 50% lead. How many grams of

each of the two alloys should be used to make an alloy that contains 82.5 g of gold and 113 g of lead?
Mathematics
1 answer:
vlabodo [156]3 years ago
6 0

Answer: 490 grams of the first alloy should be used.

30 grams of the second alloy should be used.

Step-by-step explanation:

Let x represent the weight of the first alloy in grams that should be used.

Let y represent the weight of the second alloy in grams that should be used.

A chemist has two alloys, one of which is 15% gold and 20% lead. This means that the amount of gold and lead in the first alloy is

0.15x and 0.2x

The second alloy contains 30% gold and 50% lead. This means that the amount of gold and lead in the second alloy is

0.3y and 0.5y

If the alloy to be made contains 82.5 g of gold, it means that

0.15x + 0.3y = 82.5 - - - - - - - - - - - -1

The second alloy would also contain 113 g of lead. This means that

0.2x + 0.5y = 113 - - - - - - - - - - - - -2

Multiplying equation 1 by 0.2 and equation 2 by 0.15, it becomes

0.03x + 0.06y = 16.5

0.03x + 0.075y = 16.95

Subtracting, it becomes

- 0.015y = - 0.45

y = - 0.45/- 0.015

y = 30

Substituting y = 30 into equation 1, it becomes

0.15x + 0.3 × 30 = 82.5

0.15x + 9 = 82.5

0.15x = 82.5 - 9 = 73.5

x = 73.5/0.15

x = 490

You might be interested in
(I NEED THIS ANSWERED SUPER SUPER FAST PLEASE IT'S IMPORTANT!!!!!!)<br><br> 6 7/8c =__ fl oz
Olegator [25]
1 cup = 8 fluid ounces.
6.875 cups = ? fluid ounces.
8*6.875=55.

Your answer would be 55 fluid ounces.
8 0
3 years ago
A lighthouse is built on an exposed reef, 4.5 miles off-shore. The shoreline is perfectly straight, and a town is located 6 mile
Alisiya [41]

Answer: 3.94 hours

Step-by-step explanation:

From the question, the following parameters are given:

Distance offshore = 4.5 miles

Distance downshore = 6 miles

Speed when running = 3.4 mph

Speed with boat = 1.8 mph

distance of boat rowing = sqrt(4.5^2 + x^2)

Where

Speed = distance/time

Time = distance/speed

Time = distance of boat rowing/1.8

distance of running = 6 - x

Time = (6-x)/3.4

total travel time

t = sqrt(4.5^2 + x^2)/1.8 + (6 - x)/3.4

dt/dx = x/(1.8×sqrt(4.5^2 + x^2) - 1/3.4

d^2t/dx^2 = +ve at any x

x is at its minimum when dt/dx=0

x/(1.8×sqrt(4.5^2 + x^2) = 1/3.4

x = 6/sqrt(253) × 4.5 = 1.697 miles

Substitute x in

t = sqrt(4.5^2 + x^2)/1.8 + (6 - x)/3.4

We obtaine

t = sqrt(4.5^2 + 1.697^2)/1.8 + (6 - 1.69)/3.4

t = 2.672+ 1.266 = 3.94 hours

7 0
3 years ago
#3 and 5 please<br> I don’t understand how to get them
denpristay [2]

Answer:

im bad with this kinda thing, just guess and start praying, goodluck

Step-by-step explanation:

6 0
2 years ago
If the slope of line L is -2/5, what is the slope of line m so that line l and line m are perpendicular?
ki77a [65]
Perpendicular lines have negative reciprocal slopes. So if the slope is -2/5...to find the negative reciprocal, " flip " the slope and change the sign.
So we flip -2/5 and we get 5/-2...and now we change the sign...and we get 5/2. So our perpendicular slope will be 5/2.
3 0
3 years ago
Does a shape with a right angle always have perpendicular sides? Explain
Aleks [24]

Answer:

Yes

Step-by-step explanation:

A right angle means that the lines will create an L or X or T when they intersect. This is exactly the definition of perpendicular, that the shapes will intersect and create at least one right angle.

3 0
3 years ago
Read 2 more answers
Other questions:
  • What are the quotient and remainder of (x^5-x^3+-5) divided by (x-2)
    9·2 answers
  • Can anyone help me do the questions that are circled with red and you don't need to do the graphing calculator thing, please
    8·1 answer
  • 118 - [121 - (11 × 11) - (-4) - 3 - 9 - 2]​
    12·1 answer
  • Help please!!! really really important​
    6·1 answer
  • Help on #6 please i really need help
    10·1 answer
  • What is the length of the side of a right triangle that has a side length of 12ft and a hypotenuse that measures 15ft
    5·2 answers
  • I cant figure out which one is wrong. I currently am at 83% correct
    7·1 answer
  • Please tell me how much it would be for 1
    9·1 answer
  • )) How many solutions does this equation have?<br> 12 + 4t - 14t = -13t - 18
    11·1 answer
  • Jamie sees a sale at the Gaming Store where all games are the same price. He buys 3 video games. His sister talks him into also
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!