A male child of 15 years, with a mental age of 9 years has an IQ of:
Intelligence quotient (IQ), is obtained by dividing the subject's mental age (as determined by the Binet-Simon scale) by his chronological age (up to the 14th year) and multiplying the result by 100. IQ of this child is = 9/15 * 100= 60 Ref: Introduction to Psychology By J. Mahmud, Page 236.
50
60
70
80