2 radical 7 + radical 7

Mrs Tan bought 4 times as many pens as notebooks and each notebook cost $8.20 more than each pen. She spent $26 more on the book

lilavasa [31]

Let x be the cost of 1 pen
then cost of 1 notebook = x + 8.20

Let y be the number of pens Tan buys
then number of notebooks Tan buys = y/4

She spent $26 more on books than on pens which means

Cost of notebooks - Cost of pens = 26
(x + 8.20) * y/4 - xy = 26

Sinplifying it

(xy + 8.20y)/4 - xy = 26
(xy + 8.20y - 4xy)/4 = 26
8.20y - 3xy = 104

She spent $394 which means

Cost of notebooks + Cost of pens = 394
(x + 8.20) * y/4 + xy = 394

Simplifying it

(xy + 8.20y)/4 + xy = 394
(xy + 8.20y + 4xy)/4 = 394
8.20y + 5xy = 1576

Now, we have two equations,

(1) 8.20y - 3xy = 104
(2) 8.20y + 5xy = 1576

Now we need to find a third equation with either x or y as the subject of any of both the previous equations.

Let's make y the subject of (2) equation

8.20y + 5xy = 1576
y(8.20 + 5X) = 1576
(3) y = 1576/(8.20 + 5x)

Let's substitute the new value of y from (3) into (1) because we rearranged (2) to from (3)

8.20y - 3xy = 104
y(8.20 - 3x) = 104
y = 104/(8.20 - 3x)
1576/(8.20 + 5x) = 104/(8.20 - 3x)
1576 * (8.20 - 3x) = 104 * (8.20 + 5x)
12923.2 - 4728x = 852.8 + 520x
12923.2 - 852.8 = 4728x + 520x
12070.4 = 5248x
12070.4/5248 = x
x = 2.3

Now find the value of y by substituting the value of x in either equation, preferably (3)

y = 1576/(8.20 + 5x)
y = 1576/(8.20 + 5 * (2.3))
y = 80

Therefore cost of 1 notebook = x + 8.20 = 2.3 + 8.20 = $10.50

8 0

3 years ago

Every month Miss Thomas pays her car loan through automatic payments from her savings account. she pays the same car loan each m

ivann1987 [24]

Im pretty sure the answer is 244.25

8 0

3 years ago

Find an equation of the line satisfying the given conditions Through (6,4); perpendicular to 3X + 5Y =38

Katyanochek1 [597]

To answer this, we will need to know:

• The slope of the equation we are trying to get
• The point it passes through using the

First, we will need to find the slope of this equation. To find this, we must simplify the equation $3x+5y=38$ into $y=mx+b$ form. Lets do it!

$3x+5y=38$
= $5y = -3x+38$ (Subtract 3x from both sides)
= $y= -\frac{3}{5}x+ \frac{38}{5}$ (Divide both sides by 5)

The slope of a line perpendicular would have to multiply with the equation we just changed to equal -1. In other words, it would have to equal the negative reciprocal.

The negative reciprocal of the line given is $\frac{5}{3}$ .

Now that we know the slope, we have to find out the rest of the equation using the slope formula, which is:

$\frac{y-y _{1} }{x- x_{1} }=m$

Substituting values, we find that:

$\frac{y-4}{x-6}= \frac{5}{3}$

By simplifying this equation to slope-intercept form (By cross-multiplying then simplifying), we then get that:

$y= \frac{5}{3}x-6$ , which is our final answer.

Thank you, and I wish you luck.

8 0

3 years ago

Read 2 more answers

PLS HELP ME ON THIS QUESTION I WILL MARK YOU AS BRAINLIEST IF YOU KNOW THE ANSWER PLS GIVE ME A STEP BY STEP EXPLANATION!!

DENIUS [597]

Answer:

B

Step-by-step explanation:

Total surface area=Sum of all figure area

=380+928+380+608=2296

6 0

3 years ago

HELPPPPPPPPPPPPPPPPPPPPPP

RideAnS [48]

Answer:omg I gotchu I just learned these for the letters for example would be q/1 times 2/7 because if you have one letter or number you ALWAYS put a one under it then u multiply another easy trick don’t butterfly multiply go straight across and example 8/1 (all ways add the one) times 3/4. Ok how to multiply that always go across so it would be 8x3 and 1x4 your answer should be 24/4 and simplify if needed

Step-by-step explanation:

4 0

3 years ago