Hi,
Translate into math:
B - 5 = 3 [A - 5] ----> EQ 1
B - 10 = 1/2 [C - 10] ----> EQ 2
SIMPLIFY EQ 1:
B - 5 = 3A - 15
B = 3A - 10 ---- > EQ 3
PLUG EQ 3 IN EQ 2
3A - 10 - 10 = 1/2 [C - 10]
SIMPLIFY
3A - 20 = C/2 - 5
3A = C/2 - 5 + 20
3A = C/2 + 15
A = C/(2*3) + (15/3)
A = C/6 + 5
ANSWER IS A
Let me know if this is the correct answer :)
Thanks,