the average height of 15 girls out of a class of 60 is 138 cm . and that of the remaining girls is 142 cm . the average height of the whole class is :
"explanation : average height of the whole class = ( 15 × 138 + 45 × 142 / 60 ) = 141 cms answer b"
divide(add(multiply(138, 15), multiply(142, const_10)), 60)