Commercial jet's speed = 2x-162 (plug this in the equation below)
Private jet's speed = x
Equation:
10(x) = 8(2x-162)
10x = 16x - 1296
6x = 1296
x = 216 (Private jet's speed)
Take the first equation and plug x value in;
2x-162
2(216) - 162 = 270 ( Commercial jet's speed)
X - the number of questions he answered correctly
y - the number of questions he answered incorrectly
There were 40 questions on the test.

The correct answers were given 5 points each, the incorrect answers were given -2 points each. He made a score of 95.

Set 40-x and (-95/2)+(5/2)x equal to each other:

Johnny answered correctly
25 questions.
Roll the dice 120 times
Number of outcomes from rolling the dice = 6
Probability of 4 falling in 1 roll = 1/6
Probability of the number of 4s in 120 rolls = 120 * 1/6
= 20 times
The probability that 4s falls in 120 dice rolls is 20 times.