During a storm, there was 9/2 inches of rain in 1/3 of an hour at this rate how much rainfall will there be in one hour?

One of the same side angles of two parallel lines is 20° smaller than the other one. find the measures of these two angles.

Solve this riddle: i am an odd number. i an less than 100. the some of my digit is 12. i am a multiple of 15. what number am i?

Prove that 16^4-2^13-4^5 is divisible by 11.