Question

A sum of money amounting to $4.40 consists of dimes and quarters. If there are 23 coins in all, how many are quarters?

Answer 1

let x = dime
y= quarter

x + y = 23
10(cent)x + 25(cent)y = 440 cents

x= 23 - y
10x + 25 y = 440

10(23 - y) + 25y = 440

230 -10y + 25y = 440

15y = 210
y = 14 quarters

Answer 2

let a be dimes and b be quarters

0.1a+0.25b=4.40
a+b=23
a=23-b

2.3-0.1b+0.25b=4.40
0.15b=2.1
b=14

a=23-14
=9

There are 14 quarters and 9 dimes :)

Answer 3

{d*10 + q*25 = 440, d + q = 23}
d = 9, q = 14