Directions – Study the information and answer the questions that follow.
A scientist measured all of the trees in an area that was once a waste dump and is now being returned to nature. The scientist made the histogram that shows the heights of the trees in the renewal area.
| 1. How many trees did the scientist measure? | Easy |
| A. 1000 B. 2200 C. 2300 D. None of these |
Answer: Option C
Explanation:
Number of trees = 300+1000+600+200+100+100 = 2300
| 2. The number of trees with height 5-9 feet is x% more than the number of trees with height 15-19 feet. What is x? | Easy |
| A. 200 B. 400 C. 100 D. None of these |
Answer: Option B
Explanation:
| 3. The number of trees with height 0-4 feet is p% more than the number of trees with height 15-19 feet. The number of trees with height 25-29 feet is q% less than the number of trees with height 15-19 feet. What is |p|: |q|? | Medium |
| A. 1:2 B. 2:1 C. 1:1 D. None of these |
Answer: Option C
Explanation:
p = ((300-200)/200)*100 = 50
-> |p|= 50
q = ((100-200)/200)*100 = -50
-> |q|= 50
Thus, |p|: |q|= 50: 50 = 1: 1
| 4. Let A = 15% of the number of trees with height 5 – 9 feet, and B = one fourth of the number of trees with height 10- 14 feet. What is (A+B)/AB? | Medium |
| A. 0.133 B. 0.0133 C. 0.00133 D. None of these |
Answer: Option B
Explanation:
A = 0.15 * 1000 = 150
B = ¼ (600) = 150
Thus, (A+B)/AB = 2A/A2 = 2/A = 2/150 = 0.0133
| 5. The scientist further selected 5% of the trees in each of the height intervals 0- 4 feet, 5 – 9 feet and 10- 14 feet; and 15% of the trees in each of the height intervals 15- 19 feet, 20 – 24 feet and 25- 29 feet for an advanced study. What is the ratio of the trees selected for the advanced study to those not selected for this study? | Medium |
| A. 31:429 B. 95:429 C. 21:429 D. None of these |
Answer: Option A
Explanation:
Trees selected = 0.05 (300 + 1000+ 600) + 0.15 (200 + 100 + 100) = 95 + 60 = 155
Trees not selected = 2300 – 155 = 2145
Ratio = 155: 2145 = 31: 429