find the least number which when divided by 12,24 , 36,42 leaves remainder 9,21 , 33,39 respectively .
"the difference of 12 - 9 = 3 , 24 - 21 = 3 , 36 - 33 = 3 , 42 - 39 = 3 lcm of 12,24 , 36,42 = 504 required number = 504 - 3 = 501 answer is b"
add(9,21, lcm(12,24, 36,42))