A cistern can be filled by two pipes in 30 and 40 min respectively. Both the pipes are opened at once, When the first pipe be turned off so that the tank may be just filled in 18 min? A. 12.5 min B. 13.5 min C. 14.5 min D. 16.5 min

What are the differences between similar triangles and congruent triangles?

What are Armstrong numbers?

All real numbers are rational numbers.

A) True

B) False

The L.C.M of the smallest 2 digit composite number and the smallest composite number is:

• (a) 12
• (b) 4
• (c) 20
• (d) 44

Are all natural numbers also whole numbers?