what is the smallest number which when diminished by 20 , is divisible 15 , 30 , 45 and 60 ?
"required number = ( lcm of 15 , 30 , 45 and 60 ) + 20 = 180 + 20 = 200 option a"
add(lcm(lcm(15, 30), lcm(45, 60)), 20)