Question

Represent 2/5, 13/9 and -30/49 on a number line. Please answer it is urgent.

Answer 1

solve solve question!!!! wait for sometime....

How many such 3-digit numbers are there?

(a) 2

(b) 4

(c) 6

(d) 8

Solution:

Let the number be 100x + 10y + z, where x, y and z are single digit numbers and x > 0.

Now the reverse number shall be 100z + 10 y + x. Now it is given that both of them are divisible by 7 and hence their difference shall also be divisible by 7.

Thus (100x + 10y + z) – (100z + 10 y + x) = 7m, where m is an integer.

This implies that 99(x – z) = 7m.

Now since 99 is not divisible by 7 therefore x-z should be divisible by 7. Again since x and z are single digit numbers their difference which is divisible by 7 would actually be 7 only, because for no value of x or z shall x-z be equal to 14 or 21 or 28 etc.

Thus we have x – z = 7 and the values that x and z can take are (9,2) and (8, 1)

Thus the numbers are of the form 1_8 and 2_9.