What is the remainder if 22 + 222 + 2222 +.....+ 22222......49 times2 is divided by 9 ?

If the sum of two natural numbers and their LCM is 89, then how many such pairs of numbers are possible?

a,b are factors of 21600.How many pairs of (a,b)are there such that hcf(a,b) = 45 ?

The smallest square no. which is exactly divisible by 2,,3,4,-9,6,18,36&60, is a)900 b)1600 c)3600 d) none of these

Find the greatest no., which will divide 215,167 and 135 so as to leave the same remainder in each case. a) 64 b) 32 c) 24 d)16