Answer: 150 boys
Step-by-step explanation:
Let the number of boys be x
Since there were 200 more girls than boys, the number of girls will be: = x + 200
Since the ratio of boys to girls was 3:7, this can be solved further below:
3/7 = x/x+200
Cross multiply
(7 × x) = 3(x + 200)
7x = 3x + 600
7x - 3x = 600
4x = 600
x = 600/4
x = 150
The number of boys enrolled is 150
Number of Girls will be:
= X + 200
= 150 + 200
= 350
Check: Number of boys / Number of girls
= 150/350
= 3/7
= 3:7
Answer:
102.00
Step-by-step explanation:
If you want to leave a 20% tip, multiply the cost by 0.20 to get the tip amount or multiply the cost by 1.20 to get the total including tip. If you want to leave a 18% tip, multiply the cost by 0.18 to get the tip amount or multiply the cost by 1.18 to get the total including tip.
<u>Question 8</u>
a^2 + 7a + 12
= (a+3)(a+4)
When factorising a quadratic, the product of the two factors should equal the constant term (12), and the sum of the two factors should equal the linear term (7). To find the two factors, list out the factors of 12 (1x12, 2x6, 3x4) and identify the pair that adds up to 7 (3+4).
An alternative method if you get stuck during your exam would be to solve it algebraically using the quadratic formula and then write it in the factorised form.
a = (-7 +or- sqrt(7^2 - 4(1)(12)) / 2(1)
= (-7 +or- sqrt(1))/2
= -3 or -4
These factors are the negative of the values that would go in the brackets when written in factorised form, as when a = -3 the factor (a+3) would equal 0. (If it were positive 3 instead, then in the factorised form it would be a-3).
<u>Question 10</u>
-3(x - y)/9 + (4x - 7y)/2 - (x + y)/18
Rewrite each fraction with a common denominator so you can combine the fractions into one.
= -6(x - y)/18 + 9(4x - 7y)/18 - (x + y)/18
= (-6(x - y) + 9(4x - 7y) - (x + y)) /18
Expand the brackets and collect like terms.
= (-6x + 6y + 36x - 63y - x - y)/18
= (29x - 58y)/18
= 29/18 x - 29/9 y
