Answer:
Surface Area: 1090 inch²
Blue Paint needed: 545 inch²
Gold Paint needed: 545 inch²
Explanation:
Is there a door or something? I'm assuming not because you didn't include it in your question.
Surface Area:
(7*15*2)+(15*20*2)+(20*7*2)=
210+600+280=
1090 inch²
If he paints half the doghouse blue and the other half gold then simply divide the surface area by 2:
1090÷2=545
He needs 545 inches² of blue paint
He needs 545 inches² of gold paint.