Find the smallest number, which when divided by 35, 40 and 60 leaves a remainder 7 in each case.

Correct option is C

Concept Used:

smallest number which is divisible by all number = LCM of these number

Solution:

lcm of 35,40,60 is  

​$$35 = 5 \times 7 \\ 40 = 2^3 \times 5 \\60 = 2^2 \times 3 \times 5 \\\text{LCM} = 2^3 \times 3 \times 5 \times 7 = 840$$ 

so the number which leaves 7 reminder when divided by 35,40,60 = lcm +7

=840+7

                                                                                                           =847