Simplify 1/3 : 2.5 : 3 3/4​

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?

Which statement is true about a number and its additive inverse? a. their product is always one. b. their sum is always one. c. they are always reciprocals of each other. d. their sum is always zero.

What is the output, or dependent variable of quantity? 1: x 2: f(x) 3: y