n is a positive integer
p = 8 x 9 x 11 x n
The remainder when p is divided by 6 | The remainder when p is divided by 33 |
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Solution
Since p has factors 8 and 9, it will be divisible by 6.
Since p has factors 11 and 9, it will be divisible by 33. There will be no remainder in either case.
Refer to the previous question
The mean (average) of the 5 annual sales figures | The median of the 5 annual sales figures |
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Solution
To find the mean, add all the values and divide by 5. (1000 + 2000 + 3000 + 2000 + 1000)/5 = 9000/5 = 1800
To find the median, arrange the numbers in order of magnitude and find the middle term
1000,1000,2000,2000,3000. The median = 2000
This question and the next refer to the following:
The graph shows the sales figures for a certain company in five consecutive years.
Percentage increase in sales from 1989 to 1991 | Percentage fall in sales from 1991 to 1993 |
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Solution
From 89 to 91 the rise is 2000. From 91 to 93 the fall is 2000.
But the percent increase is (2000/1000) x 100; and the percent fall is (2000/3000) x 100
Therefore, the percent rise is greater.
C is the midpoint of segment AE and AB < DE
BC | CD |
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Solution
BC = AC - AB
CD = CE - DE, but AC and CE are both equal. Since DE is greater than AB, CD must be less than BC. (We are taking off a smaller amount from half the segment, when we subtract AB from AC.)
There are 28 students in a class all born in 1990
The probability that all their birthdays are in February | The probability that all their birthdays fall on a Friday |
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Solution
There are 12 months in a year so each student has a 1/12 chance of being born in a particular month. There are only 7 days in a week, so each student has a 1/7 chance of being born on a particular day of the week The chances that all will be born on a particular day of the week is thus higher than the chances of them all being born in the same month.
The sum of all the integers from -10 to 12 inclusive. | 23 |
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Solution
The sum of the integers from -10 to 10 inclusive is 0. (-10 + 10, -9 + 9, -8 + 8 etc.) This leaves only 11 and 12 to be added = 23
Three boxes contain 20, 25 and 27 sweets respectively.
The least number of sweets that need to be transferred so that there is an equal number in each box. | 5 |
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Solution
The total number of sweets = 20 + 25 + 27 = 72
If there are an equal number in each, there will be 72/3 = 24
To make the numbers equal we will need to remove one from the second box, and three from the third (and put them in the first). This means we must move 4 sweets.
A circle and a line lie in the same plane.
The greatet possible number of points that are on both the circle and the line. | 2 |
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Solution
The line can cut through the circle at maximum two points.
p + q = 3, and p-q = 6
q | 0 |
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Solution
These are a pair of simultaneous equations. To solve, we can add them to get
2p = 9. p = 4.5
Substituting in the first equation 4.5 + q = 3; q = -1.5
So 0 is greater than q
x is 3 less than y
x + 5 | y + 2 |
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Solution
x is 3 less than y can be written x = y - 3
If we add 5 to both sides we have x + 5 = y + 2