1. 10cm^3 of a normal specimen of human blood contains 1.2g of hemoglobin. How many grams does 21cm^3 of the?

Question

same blood contain?

2. It is known that making 1lb. of honey requires 20,000 trips by bees to flowers to gather nectar. How many pounds of honey would 65,000 trips produce?

3. Last season a major league baseball player got 140 hits in 200 times at bat. If the player expects to bat 500 times in the entire season with the same ratio of hits to at bats, how many hits can the player expect to have?

4. A sample of 142 firecrackers contained 5 duds. How many duds would you expect in a sample of 2698 firecrackers?

5. Find the variation constant and an equation of variation where y varies directly as x and y=54 when x=6

Answer 1

For all these problems (except 5), you can easily set up a proportion.
1. Set up a proportion. 10 cm^3/1.2g as 21cm^3/ x g. Then solve for x. You would cross multiply and get 25.2 = 10x or x = 2.52 grams of hemoglobin

2. Proportion-> 1 lb is to 20000 trips as x lbs is to 65000 trips. 1/20000 = x/65000 -> 65000=20000x x = 65/20 lbs. = 3 1/4 lbs.


3. Again set up a proportion. It is 140 hits to 200 balls, so it is x hits to 500 balls. Thus the proportion would be 140/200 = x/500. Cross multiplying and simplifying would result in 3500=10 x. Thus x = 350 hits

4. 142 firecrackers is to 5 duds as 2698 firecrackers is to x duds.
5/142 = x/2698 ->13490 = 142x.x= 95

5. For direct variation problems, where one var. directly varies with another, the equation is always y =kx. Plugging in y=54 and x=6, results in 54 = 6k, or k =9. Thus the equation of variation is y=9x

Answer 2

Question 1
10 cm³<--->1.2 g
21 cm³<---> (21 / 10) x 1.2 g = 2.52 g

Question 2
20 ,000 trips<-->1 lb
65,000 trips<--->65,000 / 20,000 lbs = 3.25 lbs

Question 3
200<--->140 hits
500<--->(500 / 200) x 140 hits = 350 hits

Question 4
142<--->5 duds
2698<-->(2698 / 142) x 5 = 95 duds

Question 5
y = k x
54 = k x 6
k = 9
y = 9 x