Question

A teacher asks each student to randomly choose a number from 1 to 90 and write it down.Keiko and Mitsugu Write down the number. What is the probability that both of their choices will be greater than 75?Express your answer as a decimal.If necessary round your answer to the nearest thousandth.

A. 0.028

B. 0.167

C. 0.972

D. 0.026

Answer 1

90-75=15
15/90=Kieko's chance of getting higher than 75
15/90=Mitsugu's chance of getting higher than 75
15/90X15/90=.0277777777
=2.78% chance

Answer 2

A. 0.028

Explanation:

Given,

The total numbers = 90 ( from 1 to 90 ),

Also, numbers greater than 75 = 90 - 75 = 15,

Keiko and Mitsugu write down numbers randomly from these numbers,

Hence, the probability that both of their choices will be greater than 75

= The probability of a number greater than 75 × the probability of a number greater than 75

=
`(15)/(90)* (15)/(90)`

=
`(225)/(8100)`

= 0.027777

≈ 0.028

Option 'A' is correct.