Answer:
Let the test scores be x1, x2, x3, x4
(x1 + x2 + x3)/3 = 88
x1 + x2 + x3 = 264
(x1 + x2 + x3 + x4)/4 = 90
264 + x4 = 360
x4 = 360-264
x4 = 96
Therefore he should get 96 marks in his 4th test to raise his mean test score to 90
The mean score is the total of all scores divided by the total no. Of tests
Hope this helps!
Answer:
-4.5
Step-by-step explanation:
15(2-x)=13(3-x)
Expand parentheses:
30-15x=39-13x
Add 15x to both sides:
30=2x+39
Subtract 39 from both sides:
2x=-9
Divide both sides by 2:
x=-4.5
Hope this helps!
Answer:
-4 1/3
Step-by-step explanation:
26 ÷ -6
= 26 / -6 (divide both top and bottom by 2)
= 13 / 3
= -13 / 3
= -4 1/3
7 + 9 *6
7 + 54
61 - final answer
The first term, a, is 2. The common ratio, r, is 4. Thus,
a_(n+1) = 2(4)^(n).
Check: What's the first term? Let n=1. Then we get 2(4)^1, or 8. Is that correct? No.
Try this instead:
a_(n) = a_0*4^(n-1). Is this correct? Seeking the first term (n=1), does this formula produce 2? 2*4^0 = 2*1 = 2. YES.
The desired explicit formula is a_(n) = a_0*4^(n-1), where n begins at 1.
