Basil asks each of 40 students how many books they bought last year.
The chart shows information about the number of books they each bought.
144
a) What is the percentage
12
of these students who
bought 20 or more books? (2)
10-
15%
Number
of
b) Work out an estimate for the
students
mean number of books bought.
8
6
4
2
0
0 to 4
5 to 9 10 to 14 15 to 19 20 to 24
Number of books
(4)
Total marks: 6

First step is to get rid of the square root. remember that a square root is the same as raising to the (1/2) power. see below: multiply exponents per exponent rules to get: remember you subtract exponents from the denominator and add exponents in the numerator so: simplify further: so a is the correct choice. if you don't understand this google exponent rules and it will you understand. look at the image results.

The answer is b. (-13).