Question

Find the product using suitable rearrangement: 2 x 99 x 25 x 4 x 50​

Answer 1

Step-by-step explanation:

Example 1: Find the number of zeros in 2145 x 5234 .

Solution:When we see the question it looks like a very difficult question but this type of question involving number of zeros is very simple and can be solved in seconds. Here the question is asking for the number of zeros, now we have to look for the pairs of 2x 5, so the maximum pairs we can form are 145 because we have the maximum power of 2 is 145 , so the number of zeros in this case are 145.

Example 2: How many numbers of zeros are there in following expression

211 x 1253 x 711+ 311 x 711x 210 x 51+ 1112 x 213 x 5125

Solution: To explain the solution we must know something about the nature of zeros, before doing this lets have a simple example, the number of zeros in the end of

10+100+1000+……………..+ 10000000000000000000 are 1 because we can take 10 common out of this expression and write it as 10(1+10+100+……………..+ 1000000000000000000) And clearly the term present inside the bracket has unit digit 1 which when multiplied with 10 results into 1 zero at its end.Thus number of zeros in any such expression will depend on the least zero holder in the expression.

Now using the same logic we can say least number of zeros will be contributed by second term i.e. 311 x 711x 210 x 51 as it contains only single power of 5 .Hence it contains only 1 zero, so the number of zeros for whole expression is 1 .

Example 3:Find the number of zeros at end of

5 x 10 x 15 x 20 x 25 x 30 x 35…………………………………… x 240 x 245 x 250

Solution: We can take 5 common out of this expression and write it as

550 (1 x 2 x 3 x 4…………………………………… x 49 x 50)

550 (50!)

Answer 2

Answer:

990000

Step-by-step explanation:

25 × 4 = 100

50 × 2 = 100

100 × 100 = 10000

10000 × 99

= 990000