The square base of a pyramid of side 3cm has height 8cm. If the pyramid is cut into two parts by a plane parallel to the base midway between the base and the vertex, the volumes of the two sections are

A.

(21cm3, 3cm3)

B.

(24cm3, 3cm3)

C.

(24cm3, 21cm3)

D.

(72cm3, 9cm3)

E.

(63cm3, 9cm3)

Correct answer is B

Vol. of the 1st section is side x height

vol. = 3 x 8

= 24cm3

vol. of the second section is 3 x 1 = 3

= 24cm3, 3cm3