Question

The probility that a stundent selected in a class will pass mathematics test is 3/5. How many selected are likely to fail mathematics in the class with 65 stundent

Answer 1

3 / 5 = 3 • 20 / 5 • 20 = 60 / 100 = 60%

100% - 60% = 40% = 40 / 100 = 0.4

0.4 • 65 = 26

26 students will not pass matematic.

OR

( 1 - 3 / 5 ) • 65 = ( 5 / 5 - 3 / 5 ) • 65 =

2 / 5 • 65 = 130 / 5 = 26

Answer 2

You can also solve this in the third way.

3 / 5 of 65 = 3 / 5 • 65 = 195 / 5 = 39

39 students will pass matematic.

65 - 39 = 26

26 students will not pass matematic.