A collection of quarters and nickels is worth $3.70. There are 22 coins in all. How many of each coin are there.

A) 13nickels
9dimes

B)9nickels
13dimes

C) 11nickels
11dimes

D)10nickels
12dimes

Question

A collection of quarters and nickels is worth $3.70. There are 22 coins in all. How many of each coin are there.

A) 13nickels
9dimes

B)9nickels
13dimes

C) 11nickels
11dimes

D)10nickels
12dimes

anonymous · Answer

Q+N=22
 Q=22-N
 25Q+5N=370 NOW SUBSTITUTE (22-N) FOR N IN THE SECOND EQUATION THUS:
 25(22-N)+5N=370
 550-25N+5N=370
 -20N=370-550
 -20N=-180
 N=-180/-20

 

 
 N=9 NUMBER OF NICKELS
 Q+9=22
 Q=22-9
 Q=13 NUMBER OF QUARTERS
 PROOF
 25*13+5*9=370
 325+45=370
 370=370

annie96 · Answer

So the answer is B.