210 ways. This is a permutation question. Thus, insert 7P3 means 7 runners there is 3 places to be occupied. (7P3=210ways)
Answer:150
Step-by-step explanation:
I SAY IT THE SECOND OPTION
Answer:
mean ≈ 25.45
Step-by-step explanation:
mean is calculated as
mean = 
We require the sum for both classes
class A
mean =
= 40 ( multiply both sides by 9 )
sum = 9 × 40 = 360
class B
mean =
= 20 ( multiply both sides by 24
sum = 24 × 20 = 480
Total sum for both classes = 360 + 480 = 840 , then mean for both classes is
mean =
≈ 25.45 ( to 2 dec. places )
Answer:
20. hours
Step-by-step explanation: