Agirl is 21 years old her brother is 1/3 her age. when the girl is 36, what will her brothers age be?

how do you figure this out

Cora bought a package of erasers. there are 4 pink erasers and 12 blue erasers. what is the ratio of pink erasers to blue erasers?

(05.02)a farmer has decided to divide his land area in half in order to plant soy and corn. calculate the area of the entire area so he knows how much soil is needed. a parallelogram with a height of 6 yards and side length 9 yards. the height forms a triangle with the slanted side of the rhombus with a base of 2.5 yards. rhombus is split into a soy half and a corn half. each bag of soil covers 40 square yards. how many bags should the farmer purchase?

Me d is also an option but i couldn't get it in the picture