Question

C + d = 60
2.5c + 1.75d = 123.75

Answer 1

(c, d) = (25, 35)

Explanation:

Multiply the first equation by 2.5 and subtract the second one:

2.5(c +d) -(2.5c +1.75d) = 2.5(60) -(123.75)

0.75d = 26.25 . . . . . . . . . simplify

26.25/0.75 = d = 35 . . . . divide by the coefficient of d

60 -d = c = 25 . . . . . . . . . use the first equation to find c

(c, d) = (25, 35)