1. 
A student got twice as many sums wrong as he got right. If he attempted 48 sums in all, how many did he solve correctly ? 


2. 
David gets on the elevator at the 11th floor of a building and rides up at the rate of 57 floors per minute. At the same time, Albert gets on an elevator at the 51st floor of the same building and rides down at the rate of 63 floors per minute. If they continue travelling at these rates, then at which floor will their paths cross ? 


3. 
I have a few sweets to be distributed. If I keep 2, 3 or 4 in a pack, I am left with one sweet. If I keep 5 in a pack, I am left with none. What is the minimum number of sweets I have to pack and distribute ? 


4. 
If a clock takes seven seconds to strike seven, how long will it take to strike ten ? 


5. 
In a group of cows and hens, the number of legs are 14 more than twice the number of heads. The number of cows is 

