Part a is correct.
Part b can be done a couple ways.
1) Use binomial distribution. p = 0.2, n = 144
P(x>3) = 1 - P(x=0) -p(x=1) -p(x=2) -p(x=3)
where

2) Assume a normal distribution with mean = 28.2, stdev = 4.8

Look up z-value in normal table to find probability.
Hope that helps.
(x,y) = (1, 1.2)
1 = 7(1) - 5(1.2)
1 = 7 - 6
There are many other options though.
Answer:
126°
Step-by-step explanation:
(2x +18)° = (3x)°
2x + 18 = 3x
18 = 3x - 2x
18 = x
therefore, (3x)° = (3*18)°= (54)°

Answer:
1300 and 700 respectively.
Step-by-step explanation:
Let x be invested in first account and y be invested in second account.
ATQ, x+y=2000 and 101=(4)*x/100+7*y/100. Solving it will give us x=1300 and y=700
Answer:
-38 degrees
Step-by-step explanation:
32-70
= -38