51/3+-39/18
= 89/6
Answer is 14.833333
So it would be 12 minutes and $5 per 12 minutes.
∠GHJ and ∠RST are complementary
⇒ ∠GHJ and ∠RST = 90°
And ∠RST and ∠ABC are supplementary
⇒ ∠RST and ∠ABC = 180°
Also, ∠GHJ = x°
⇒ ∠RST = 90° - x°
⇒ ∠ABC = 180° - ∠RST
⇒ ∠ABC = 180° - (90° - x°)
⇒ ∠ABC = 90° + x°