Lulu tells her little brother, Jack, that she is holding 20 coins, all of which are either dimes or quarters. They have a value of $4.10. She says she will give him the coins if he can tell her how many of each she is holding. Solve this problem for Jack.

Question

Lulu tells her little brother, Jack, that she is holding 20 coins, all of which are either dimes or quarters.  They have a value of $4.10.  She says she will give him the coins if he can tell her how many of each she is holding.  Solve this problem for Jack.

TWALKER16 · Answer

25q+10d=410, 25q+10(20-q)=410, 25q+200-10q=410, 15q+200=410, 15q=210, q=14, and since d=20-q, d=6, 14 quarters and 6 dimes.