SOLUTION: David has a total of 4.10 pesos in 5 cent, 10 cent and 25 cent coins. He has twice as many 5 cent coins and two more 25 cent coins than 10 cent coins. How many 10 cent coins does h

Algebra ->  Coordinate Systems and Linear Equations  -> Lessons -> SOLUTION: David has a total of 4.10 pesos in 5 cent, 10 cent and 25 cent coins. He has twice as many 5 cent coins and two more 25 cent coins than 10 cent coins. How many 10 cent coins does h      Log On


   

Question 1150100: David has a total of 4.10 pesos in 5 cent, 10 cent and 25 cent coins. He has twice as many 5 cent coins and two more 25 cent coins than 10 cent coins. How many 10 cent coins does he have?
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
system%285n%2B10d%2B25q=410%2Cn%2Fd=2%2Cq-d=2%29

system%28n%2B2d%2B5q=82%2Cn=2d%2Cq=d%2B2%29

Question asks for d.
Simple substitution gives 2d%2B2d%2B5%2A%28d%2B2%29=82.
Solving for d should give a whole value.

9d%2B10=82
9d=72
d=72%2F9
highlight%28d=8%29