math
posted by reena on .
Bill buys x items at $3 each, y items at $5 each, and z items at 6 each. If x,y,and z are each multiple of 5 and the total price of the items costing $3 and $5 is 55, which of the following could be the total price of all x +y+z items?
a. 66 b. 80 c. 95 d. 145 d. 150

i got it, thank you for giving the hint. It is d, since after subtracting 55, the only divisible by 6 that has a multiple of 5 is d.

There must be 10 costing $3 and 5 costing $5. That adds up to $55. The number of z's sold must be a multiple of 5 and the amount spent on z's must be a multiple of 6 x 5 = 30.
$145 (d) is a possibility if 15 z's are sold.