Ask question

Ask question

All categories

Artyom0805 [142]

3 years ago

14

Every evening Jenna empties her pockets and puts her change in a jar. At the end of the week she counts her money. One week she

had 40 coins, all of them dimes and quarters. When she added them up, she had a total of $7.75. Let d= number of dimes and q= number of quarters

1 answer:

Sergeeva-Olga [200]3 years ago

6 0

A) .10 d + .25 q = 7.75
B) d + q = 40

Multiplying B) by -.10
B) -.10d -.10q = -4.0
Then adding this to A)
A) .10 d + .25 q = 7.75
.15q = 3.75

Quarters = 25
Therefore, dimes = 15
***************************************************
Double-Check
A) .10 d + .25 q = 7.75
A) .10 * 15 d + .25 * 25 = 7.75
A) 1.50 + 6.25 = 7.75

Correct!!

You might be interested in

Explain how to find simple interest

mr_godi [17]

Answer:

Simple interest is calculated by multiplying the daily interest rate by the principal, by the number of days that elapse between payments.

Step-by-step explanation:

Principal x rate x time = interest.

$100 x .05 x 1 = $5 simple interest for one year.

$100 x .05 x 3 = $15 simple interest for three years.

7 0

3 years ago

Read 2 more answers

Math question down below

Alja [10]

Answer:

E

E is the only one that ends with 70 and is also all multiples of 6.

4 0

4 years ago

Evaluate f(2). f(x)=3x-1

amid [387]

It’s going to be 2..

6 0

3 years ago

M<br> (2y+19)<br> (5x+20)<br> n<br> (4x-11)

AleksandrR [38]

Answer:

(5x+20)+(4x-11)=180(linear pair)

9x+9=180

9x=180-9

9x=171

x=171/9

x=19

now,

(2y+19)+(5x+20)=180(co-interior angle)

2y+19+5×19+20=180

2y+134=180

2y=180

y=180/2

y=90

7 0

3 years ago

Pls solve the simultaneous equation in the attachment.

siniylev [52]

Answer:

Part a) The solution is the ordered pair (6,10)

Part b) The solutions are the ordered pairs (7,3) and (15,1.4)

Step-by-step explanation:

Part a) we have

$\frac{x}{2}-\frac{y}{5}=1$ ----> equation A

$y-\frac{x}{3}=8$ ----> equation B

Multiply equation A by 10 both sides to remove the fractions

$5x-2y=10$ ----> equation C

isolate the variable y in equation B

$y=\frac{x}{3}+8$ ----> equation D

we have the system of equations

$5x-2y=10$ ----> equation C

$y=\frac{x}{3}+8$ ----> equation D

Solve the system by substitution

substitute equation D in equation C

$5x-2(\frac{x}{3}+8)=10$

solve for x

$5x-\frac{2x}{3}-16=10$

Multiply by 3 both sides

$15x-2x-48=30$

$15x-2x=48+30$

Combine like terms

$13x=78$

$x=6$

<em>Find the value of y</em>

$y=\frac{x}{3}+8$

$y=\frac{6}{3}+8$

$y=10$

The solution is the ordered pair (6,10)

Part b) we have

$xy=21$ ---> equation A

$x+5y=22$ ----> equation B

isolate the variable x in the equation B

$x=22-5y$ ----> equation C

substitute equation C in equation A

$(22-5y)y=21$

solve for y

$22y-5y^2=21$

$5y^2-22y+21=0$

Solve the quadratic equation by graphing

The solutions are y=1.4, y=3

see the attached figure

<em>Find the values of x</em>

For y=1.4

$x=22-5(1.4)=15$

For y=3

$x=22-5(3)=7$

therefore

The solutions are the ordered pairs (7,3) and (15,1.4)

3 0

4 years ago