 Hello and welcome to the session. My name is Mansi and I am going to help you with the following question. The question says IQ of a person is given by the formula IQ equals to MA divided by CA into 100 where MA is mental age and CA is chronological age. If AT is less than equal to IQ is less than equal to 140 for a group of 12 years old children find the range of their mental age. So let us start with the solution to this question. We see that IQ of a person is given by the formula IQ equals to MA divided by CA into 100 where we see MA is the mental age and CA is the chronological age. Now it is given that CA equals to 12 years and AT is less than equal to IQ is less than equal to 140 therefore AT is less than equal to MA divided by CA into 100 is less than equal to 140. Now let MA be equal to X therefore AT into 12 is less than equal to 100 X is less than equal to 140 into 12. Now these are two inequalities and we shall solve them simultaneously. Now we can write this as 960 is less than equal to 100 X is less than equal to 1680 or 9.6 is less than equal to X is less than equal to 16.8. Hence MA should be at least 9.6 but not more than 16.8. So this is our answer to this question. I hope you understood the question and enjoyed the session. Have a good day.