The temperature at 9 pm was -4.2 degrees since from 8 pm to midnight the temperature fell constantly at a rate of -4.2 degrees per hour.
A. 21*(2/3) = 14 -----> not 3/2 (X
B. 7*(2/3) = 14/3 ----> not 14 (X
C. 21*(2/3) = 14 -----> equal 14 (O
D. 28*(2/3) = 56/4 -> not 42 (X
E. 42*(2/3) = 28 ----> equal 28 (O
F. 14*(2/3) = 28/3 --> not 21 (X
so the answer is C and E
<span>Sally's rate is 1/4 job per hour.
Kathy's rate is 1/6 job per hour.
Can you solve the rest? Scroll down if you can't!
1/4 + 1/6
= 3/12 + 2/12
= 5/12
5/12 x 6 = 30/60.
Answer: It will take them half an hour combined. </span>