Aschool has 320 girls and 250 boys the probability of a girl being left handed is 0.2 the probability of a boy being left handed is 0.1 estimate the amount of left handed people there are in the school

95

Step-by-step explanation:

For this we need to find the amount of left handed boys and left handed girls.  Lets go first with boys.

As there are 250 and the probability that a boy is left handed is 0.1 (or 10%) we can find the amount of left handed boys by simply the product of both numbers:

leftboys= 250 * 0.1 = 25

We can do the same for girls, as there are 350 girls with a probability of being left handed of 0.2 (or 20%) for any of them:

leftgirls = 350 * 0.2 = 70

So, the total amount of left handed people is:

letftotal = lefboys + leftgirls = 25 + 70 = 95

one that is bigger than 3 1/2

b. 1.25 hr

step-by-step explanation:

if you have a constant speed of 60 mph, then you have a ratio between 60 mi. to 1 hr. dividing both sides by 60 we get the ratio

1 mi. to

then mult. both sides by 75 we get the ratio

75 mi. to

simplifying we get

75 mi. to

or 1.25 hr.