Answer:
12 g
Step-by-step explanation:
Recall that
Average Weight = Sum of All weights ÷ Number of Weights
in the first case we are given that average of 5 weights is 13g
i.e Average weight (of 5 weights) = 13g and number of weights = 5
or, using the formula above,
13 = sum of 5 weights ÷ 5 (rearranging)
sum of 5 weights = 13 x 5 = 65 g
we are subsequently told that one more weight of 7 g is added,
hence, new number of weights = 6
and,
sum of 6 weights = sum of original 5 weights + sum of 6th weight
= 65 g + 7 g = 72 g
once again using the first formula
Average Weight (of 6 weights) = Sum of All weights ÷ Number of Weights
= 72 ÷ 6
= 12g