You haven't shared the possible answers, so the best I can do (which is very good!) is to assume we want to change from base 4 to base 10 and then apply the change of base formula.
Given log-to-the-base-4-of (x+2), we want log-to-the-base-10 of (x+2). Following the change of base formula,
log-to-the-base-4-of (x+2)
log-to-the-base-10 of (x+2) = ------------------------------------
log-to-the-base-4-of-10
The factor of this expression would be 2(x+1)
The probability that student scored more than 850 we shall proceed as follows:
z=(x-μ)/σ
where:
x=850
μ=750
σ=50
thus
z=(850-750)/50
z=2
thus
P(x>850)=1-P(x<850)=1-P(z<2)=1-0.9772=0.0228
Answer: P(x>850)=0.0228
Answer:
4/8 = 20/x
20 x 8 = 160
160 ÷ 4 = 40
the student will attend 40 weeks of school