Question

37. How many zeroes are there at the
end of the following product ?
1 x 5 x 10 x 15 x 20 x 25 x 30 x 35
X 40 X 45 X 50 X 55 X 60
(A) 10
(B) 12
(C) 14
(D) 15​

Answer 1

Step-by-step explanation:

can be written as (5*15*25*35*45) * (10*20*30*40*50)

it can also be written as (5*15*25*35*45) * (1*2*3*4*5) * (100000)

Note that 5*2=10, 5*3=15, 5*5=25.So zeroes can only be obtained when 5 gets multiplied to 2(even no.) otherwise we get 5 at the one’s place.

Now we will try to pair(Not Solve) and get 0s:

(5*15*25*35*45) * (1*2*3*(2*2)*5) * (100000)

= [(5*2)*(15*2)*(25*2)*100000] *(1*3*5*35*45). The numbers in the bolds are the pairs we can get 0s from. Rest of the Nos. will not give us zeroes when multiplied.

= 10*30*50*100000