∠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°
Number of eggs that can be bought from the shop must be in the form
E=4k + 6m + 9n + 20j
I will continue later ~