Which sentence is grammatically incorrect? (A)

If 33 @ 16 = 15' and 41 @ 32 = 7', then 64 @ 33 = ?'. What will come in place of question mark?

By interchanging the given two signs which of the following equation will be not correct?

× and –

Select the set in which the numbers are related in the same way as are the numbers of the following sets.

Select the option that is related to third number-cluster in the same way first number cluster is related to second number-cluster.

Select the option that is related to the third letter-cluster in the same way as the second letter-cluster is related to the first letter-cluster.

How many numbers are immediately preceded and succeeded by symbol?

6 7 @ # 2 8 8 $ 5 4 % 5 ! & # * 7 * + 9

Select the option that is related to third letter cluster in the same way second letter cluster is related to first letter cluster.

Select the option in which the numbers are not related in the same way as are the number of the following set.

(43, 55, 80)