Solve for x the pair of polygons are similar

the answer would be c:   ax + b = ax + c

step-by-step explanation:

30,40,50 is correct answer

let x be volume of 1% and let y represent volume of 7% solution.

then the amount of minoxidil is

0.01x + 0.07y = 0.05(x+y)

but we have that x = 90 ml so

0.01(90) + 0.07y = 0.05(90+y)

0.9 + 0.07y = 4.5 + 0.05y

0.02y = 4.5-0.9

y = 3.6/ 0.02

y = 180 ml

she should add 180 ml of 7%