What mark do I need?

Question

If one module in university represents 100%

and it is split into 2 sections - one piece of work worth 20% and the other piece of work worth 80%.

If i gained 63 in the 20% section what mark would i need in the 80% piece to get an overall average of 70.??

Thanks

Answer 1

You get:

70 = 0.2*63 + 0.8*x <=> x = 71.75

So you need at least 72 in the second piece of work.

Answer 2

You got 63 in the 20% section = 63 X 0.2 = 12.6 marks.

You need a total of 70 and so the balance needed is 70 - 12.6 = 57.4 which works out to 57.4/80 = 71.75 or say 72 marks.

Another way of doing the same problem is this:

-7 X 0.2 = -1.4 and that is to be nullified by 0.8 of x. So,

x = 1.4/ 0.8 = 1.75 or nearly 2

Answer 3

To get at least a 70, you would need a 71.75, or 72, in the 80% section. This is how i came to this conclusion:

You got a 63 in the 20% section, so
63 * 0.2 = 12.6 points

You need 70 so find the difference:
70-12.6 = 57.4

which means you need to get at least 57.4 points FROM the 80% section added to that. To find out what score you need to GET, set up the equation like this:
0.8x = 57.4
x = 71.75

and then round up to 72, just to be safe.

To check this:
(63 * 0.2) + (72 * 0.8) = 12.6 + 57.6 = 70.2

Answer 4

Gain in the 20% section = 63
What to gain in the 80% section so that

(63 + x) / 2 = 70

Multiply by 2

63 + x = 140
x = 140 - 63
x = 77 ===> the mark that you need in the 80% so that your average will be 70.

What your score should be ?

80% of x = 77
x = 77/80%
x = 77/.80
x = 96.25 ===> you should score 96.25 in the 80% section to get 77

Answer 5

your 63 is one fifth of your total grade. This is 20% in fraction form. So multiply it by 1/5 then take a value x which will represent your grade in the 80% piece and multiply that by 4/5, which is fraction form of 80%. so the equation is as follows

(63+4x)/5>70

now solve the equation by multiplying by 5

63+4x>350

subtract 63

4x>287

divide by 4

x>71.75

So your minimum grade would be a 71.75

Answer 6

u need 71.75 72%
63*.2 = 12.6
70-12.6 = 57.4
57.4/.8 = 71.75

Answer 7

63 * (0.2) + x (0.8) = 70

x = 71.75