Question

The mean of 20 numbers is 20 if 2 is added to each of the first 10 numbers find the mean of the new set of 20 numbers

Answer 1

Step-by-step explanation:

$20 = (a + b.......) \div 20 \\ 40 =( a + b...) \\ a + b..... + 2 \times 10 \\ new \: sum \: is \: a \: plus \: b \: plus \: so \:on \: plus \: 20 \\ so \: avg \: is \: 20 \div 20 \\ = 1$