In a class of 35 students, 17 have taken mathematics,
% have taken mathematics but not
economics. If each student as taken at least one subject, find the number of students who have taken
economics but not mathematics​

If tan2a=cot(a+60), find the value of a, where 2a is an acute angle

If johnny ate 5 cans of sugar, but in the kitchen they only had 3. what did johnny eat? (he found a secret stash btw.)

Aliter of water contains about 3.35 x 10^25 molecules. a certain river discharges about 2.9x 10^8 l of water every second. about how many molecules does the river discharge every minute? write your answer in scientific notation