ALGEBRA
posted by AMBER .
A hardware supplier manufactures three kinds of clamps, types A, B, and C. Production
restrictions force it to make 10 more type C clamps than the total of the other types
and twice as many type B clamps as type A clamps. The shop must produce 250 clamps per day.
How many of each type are made per day?
How many type A clamps are produced?
How many type B clamps are produced?
How many type C clamps are produced?

a+b+c = 250
c = 10 + (a+b)
b = 2a
rearrange things a bit:
a + b + c = 250
a  b + c = 10
2a + b = 0
add the top two to get
2c = 260
c = 130
a+b130 = 10
a+2a130 = 10
3a = 120
a = 40
b = 80