math
posted by Cheril on .
Select the equation that solves this problem:
Eight coins (dimes and quarters) are worth 170 cents. How many dimes are
there?
a. 10d + 25(11  d) = 170
b. 10d + 25(8  d) = 170
c. 10d + 5(8  d) = 60
d. 10d + 5(11  d) = 60

So what do you think?

I send to you solution for simmilar problem.

A quarters is worth 25 cents and a dime is worth 10 cents.
q = numbers of a quarters
d = numbers of a dimes
q + d = 8
q = 8  d
Value of money :
10 ¢ * d + 25 ¢ * q = 170 ¢
10 d + 25 q = 170
10 d + 25 ( 8  d ) = 170
Equation b.
10 d + 25 ( 8  d ) = 170
10 d + 25 * 8 + 25 * (  d ) = 170
10 d + 200  25 d = 170
10 d  25 d = 170  200
 15 d =  30 Divide both sides by  15
d =  30 /  15
d = 2
q = 8  d = 8  2 = 6
2 dimes and 6 quarters
2 * 10 ¢ + 6 * 25 ¢ =
20 ¢ + 150 ¢ = 170 ¢