The table shows the battery life of four different mobile phones:

Mobile Phone Battery Life
Phone: Battery Life (hours)
A: 20
B: 25
C: 10
D: 18

If 8.45% of the battery life of each mobile phone is used in a day by a typical user, for which mobile phone is 0.8 hour of battery life used in a day?

1. Phone A
2. Phone B
3. Phone C
4. Phone D

Aclassroom is made up of 11 boys and 14 girls. the teacher has four main classroom responsibilities that she wants to hand out to four different students (one for each of the four students). if the teacher chooses 4 of the students at random, then what is the probability that the four students chosen to complete the responsibilities will be all boys?

Lian is deciding which of two gyms to join. each gym charges a monthly rate plus a one-time membership fee. lian correctly wrote and solved a system of linear equations by substitution to compare the costs of the memberships. in her work, she substituted an expression for one variable and solved for the other. this resulted in the equation 75 = 75. what can lian conclude? one gym charges $75 per month. each gym charges $75 per month both gyms charge the same monthly rate and the same membership fee. both gyms charge the same monthly rate, but not the same membership fee.

Which values of m and b will create a system of equations with no solution? y=mx+b y=-2x+3/2