Please help, I have to have this in in 30 minutes.

Joe has a collection of nickles and dimes that is worth $7.65. If the number of dimes was doubled and the number of nickles was increased by 35, the value of the coins would be $14.30. How many nickles and dimes does he have? Show your work.

Question

Please help, I have to have this in in 30 minutes.

Joe has a collection of nickles and dimes that is worth $7.65. If the number of dimes was doubled and the number of nickles was increased by 35, the value of the coins would be $14.30. How many nickles and dimes does he have? Show your work.

anonymous · Answer

two equations:
10d+5n=765
10(2d)+5(n+35)=1430

solve for n and d:

5n=765-10d
n=153-2d

plug in to other equation:

20d+5((153-2d)+35)=1430
20d-10d+940=1430
10d=490
d=49

so 49 dimes and:

n=153-2(49)
n=55

49 dimes and 55 nickles