Question

(a) The mean of the masses of a group of four student is 30 kg.

One student joins the group .The mean of the masses of the five students is 32 kg.
Find the mass of the student who joined the group.


(b)The mean of the five articles is 215 g. When another article is added, the mean of the masses of the six articles is 220 g. Find the mass of the sixth article.

Answer 1

a) 40kg b) 245g

Explanation:

a) the total mass of the group of 4 students is 30 x 4 = 120

the total mass of the group of 5 students is 32 x 5 = 160

160 - 120 = 40

b) the total mass of 5 articles is 215 x 5 = 1075

the total mass of 6 articles is 220 x 6 = 1320

1320 - 1075 = 245