Arctan(tan(105°)) = 105° true false

How do i do this activity, is appreciated

Helll ! 1,400 tons of wheat of two different varieties was delivered to the silo. when processing one variety, there was 2% of waste and 3% during the processing of the second variety of wheat. after the processing, the amount of remaining wheat was 1,364 tons. how many tons of each variety of wheat was delivered to the silo?

Present age of man is 45 years, 5 years back his age was 4 times age of his son what is present age of his son?