Robin randomly selects a number between 1 and 20. what is the probability that the number selected is the square of a natural number?
a.1/2
b.-3/20
c.-3/10
d.1/5
e.1/3

Work out square numbers from 1 to 20
1 (1x1=1), 4 (2x2=4), 9 (3x3=9), 16 (4x4=16)
Probability is 4 out of 20 = 4 / 20, simplified is 1 / 5 (4 into 4 is 1, 4 into 20 is 5)
therefore the probability that the number Robin selects randomly is a square of a natural number is 1/5.