Question

A girl has 11 coins in dimes and quarters. Their value is $1.55. How many quarters does she have?

8
3
5

Answer 1

she has 3 quarters

Explanation:

let's call the amount of dimes D

let's call the amount of quarters Q

you know that she has 11 coins in total,

so D + Q = 11.

you also know that each dime is worth 10 cents.

and each quarter is worth 25 cents.

so 10d + 25q = 155

this is a system of equations. solve by substitution:

d = 11 - q

10d + 25q = 155

10(11 - q) + 25q = 155

110 - 10q + 25q = 155

15q + 110 = 155

15q = 45

q = 45/15

q = 3