Question

Jimmy has seven times as many dimes as nickels. Their value is $3.75. How many nickels does he have?

Answer 1

Answer:

the number of nickels is $5$

Step-by-step explanation:

Let

x------> the number of nickels

y------> the number of dimes

we know that

$1\ nickel=\ 0.05$

$1\ dime=\ 0.10$

so

$0.05x+0.10y=3.75$ -------> multiply by $100$ both sides

$5x+10y=375$ -------> equation A

$y=7x$ -------> equation B

Substitute equation B in equation A and solve for x

$5x+10[7x]=375$

$5x+70x=375$

$x=375/75$

$x=5$

Find the value of y

$y=7(5)=35$

Answer 2

.05n + .10d = 3.75
d = 7n

now we sub
.05n + .10(7n) = 3.75
.05n + .70n = 3.75
.75n = 3.75
n= 3.75/0.75
n = 5

d = 7n
d = 7(5)
d = 35

so he has 5 nickels and 35 dimes