D. (9x-4)^2
You can get this by taking the square roots of the outside terms. Then multiply them together and then by 2. For this you should get the middle term.
Answer:
The age of Mr. Collins is 30 years and
The model which represent the problem is, The age of Mr. Collins is 3 × 10
Step-by-step explanation:
Given as :
The age of Adam = 10 years
The age of Mr. Collins = x years
The age of Mr. Collins = 3 times the age of Adam
Or, x = 3 × The age of Adam
Or, x = 3 × 10
∴ x = 30
So, The age of Mr. Collins = x years = 30 years
The model which represent the problem is, The age of Mr. Collins = 3 × 10
Hence The age of Mr. Collins is 30 years and
The model which represent the problem is, The age of Mr. Collins = 3 × 10
Answer
To the left of the vertical bar are the tens places. As we want to find the scores greater than 90, we start at the row in the stem and leaf plot with a 9 to the left. To the right are 6 values - 1, 2, 3, 4, 6, and 7. So there are six scores here higher than 90: 91, 92, 93, 94, 96, and 97. Now we move lower to 10 in the tens place. There is one score there - 100. (That smart kid.)
Total up the six scores in the 9 row and the 1 in the 10 row to get 7 scores higher than 90 in this stem and leaf plot.
Thus, there are 7 scores - choice B - in the plot higher than 90.