Question

Sally has seven times as many dimes as nickels. Their value is $3.00. How many nickels does she have?

Answer 1

0.5+0.10(7n)=3
0.05n+0.70n=3.00
0.75n=3.00
n=4
4 nickels and 28 dimes.

Answer 2

Sally is having 4 nickels.

Explanation:

let the number of nickels Sally is having = x

and number of dimes she is having = y

We know dime represents 0.10 cents and nickel represents .05 cents

therefore y = 7 x ------(1)

0.10 x + .05 y = 3

10y + 5x = 300

2y + x = 60 -------(2)

By putting the value of y from equation 1 in equation 2

14x + x = 60

15x = 60

x = 60/15 = 4

y = 7×4 = 28

Sally is having 4 nickels.