book Maths Puzzle Numerical Ability

A ROOM MEASURES 3M BY 4M BY 7M.
THE WALLS NEED 2 COATS OF PAINT. A 4-L CAN OF PAINT COVERS 40M SQUARED.
HOW MUCH PAINT SHOULD TANYA BUY?
I KNOW THE ANSWER BUT NOT HOW I GOT IT.

Read Solution (Total 0)

book Other Question

-1/(w-1)+4+5/(w-4)=0 x^4 -3x^2-4=0