Mrs. William's class is doing coin drive to raise money for a charity. Students have brought a total of 64 quarters and nickels . The students have raised a total of $ 12. Find the number of quarters Mrs. William's class has collected .

Respuesta :

q=quarter
n=nickel
q+n= 64
.25q+.05n= 12
Times 100
25q+5n= 1200
-25(q+n=64)
-25q-25n= -1600

25q+5n = 1200
-25q-25n = -1600
-20n = -400
Divide -20 on both sides
n=20
There are 20 nickels

q+n= 64
q+20=64
Subtract 20 on both sides
q=44
There are 44 quarters

Check work
.25(44) + .05(20) = 12
11 + 1 =12
20 nickles and 44 quarters