How many combinations with repetition are allowed if n = 5 and r = 3?
120
125
10
35

Can someone me with this problem i don't understand i need

According to the 2008 u.s. census, california had a population of approximately 4 × 10^7 people and florida had a population of approximately 2 × 10^7 people. which of the following is true? a. the population of florida was approximately two times the population of california. b. the population of florida was approximately twenty times the population of california. c. the population of california was approximately twenty times the population of florida. d. the population of california was approximately two times the population of florida.

What number is 7 units left of -15?