Question

The mean of a certain number of observations is 32. Find the observation is, (1) increased by 3 (ii) decreased by 7 (ili) multiplied by 2 (iv) divided by 0.5 (V) increased by 60% (vi) decreased by 20%​

Answer 1

(i) Increased by = 3

Observed mean = 32

If increased by 3, resulting mean = 32 + 3 = 35

(ii) Observed mean = 32

Decreased by = 7, resulting mean = 32 – 7 = 25

(iii) Observed mean = 32

Multiplied by = 2, resulting mean = 32\times2=64

(iv) Observed mean = 32

Divided by = 0.5, resulting mean = \frac{32}{0.5}=64

(v) Observed mean = 32

Increased by = 60%, resulting mean = 32+\left(\frac{60}{100}\right)

=\frac{3200+60}{100}=\frac{3260}{100}=32.6

(vi) Observed mean = 32

Decreased by = 20%, resulting mean = 32-\frac{20}{100}

=\frac{3200-20}{100}=\frac{3180}{100}=31.8