Answer:
91
Step-by-step explanation:
Mean is calculated as
mean = 
let x be his test score of his last test , then
= 85 ( multiply both sides by 7 )
504 + x = 595 ( subtract 504 from both sides )
x = 91
Answer:
Speed of boat in still water is 6km/h
Speed of current is 4km/h
Step-by-step explanation:
We know speed = distance / time
Let the speed of boat in still water be x
Let the speed of current be y
Hence the speed of boat, down stream = 
Distance downstream = 20km
Time taken = 2 hours
We have

......(1)
Speed of boat upstream = 
Distance upstream = 4
Time taken = 2
We have

...(2)
Adding (1) & (2)


Substituting in (1) we get

9514 1404 393
Answer:
52°, 40°, 88°
Step-by-step explanation:
Let x represent "one angle". This is 30% larger than "the other", so we have ...
x = "the other" × (1 +30%)
x/1.30 = "the other"
If x is 36° smaller than the third, then the third is x+36.
__
The sum of the angles is 180°.
x + x/1.3 + (x +36) = 180
x(2 +1/1.3) = 144
x = 144/(2 +1/1.3) = 52
x/1.3 = 52/1.3 = 40
x +36 = 88
The angles of the triangle are 52°, 40°, and 88°.
X = 11 x cos(22) = 10.199 = 10.2