The weights of 4 boxes are 30, 40, 50 and 80 kilograms. Which of the following cannot be the total weight, in kilograms, of any combination of these boxes and in a combination a box can be used only once?

If two is subtracted from each odd digit and three is added to each even digit in the number 3675249 how many digits will appear twice in the new number thus formed?

A man takes 6 km distance to go around the rectangular area. If the area of the rectangle is 2 sq. km. find the difference between length and breadth.

If “*” denotes “added to”, “&” denotes “divided by”, “@” denotes “multiplied by” and “%” denotes “subtracted from”, then
399 & 19 @ 21 % 41 * 100 =?

In the following questions, correct the equation by interchanging two signs.
9 × 3 + 8 ÷ 4 – 7= 28

If ‘+’ stands for division, ÷ stands for multiplication, multiplication stands for addition; then which one of the following equation is correct?

In a school, the bell is rung once after each half an hour. The school starts at 8:00 a.m. and closes at 1: 30 p.m. The bell is rung 3 times continuously, at the time of beginning, at the time of lunch break at 10:00 and 10:30 a.m. and at the end. How many times is the bell rung every day?