So for the first one think of it as decimals so it’s easier: 9.20-7.35, subtract and it would be 1.85 so since we use decimals to make it easier it isn’t actually a decimal so it would be 2 hours and 25 minutes. And for the second one you just add 50 minutes to that and you would get 3 hours and 15 minutes.
In this question, the thing that needs to be found is the number whose 20% would be 18. The information's required for getting to the solution are already provided in the question. based on those given information's, the answer can be deduced very easily.
Let us assume the unknown number to be = x
Then
(20/100) * x = 18
x/5 = 18
x = 18 * 5
= 90
so the unknown number in the question is 90. I hope the procedure is clear enough for you to understand.
The height of the blue spruce was 45.
We find the mean by adding all of the data points and dividing by the number of data points. We will add the unknown value x and change the number we're dividing by to 7:
(160+320+100+110+200+220+x)/7 = 165
(1110+x)/7 = 165
Multiply both sides by 7:
1110 + x = 1155
Subtract 1110 from both sides:
x = 45
This is the formula for the surface area of a cylinder including the ends, like the total surface area of a can of peas.
S = 2·π·r² + 2·π·r · H
Divide each side by 2·π·r :
S/2·π·r = r + H
Subtract r from each side :
H = (S/2·π·r) - r
or
H = (S - 2·π·r²) / (2·π·r)
Since 93p+84=85
subtract 84 from both sides
93p=1
p=(1/93)
