11. Two
in the ratio 3:5
When 8 is added to each the nation
changes to 5:7 Identify the
numbers
Answers
Explanation:
Two numbers are in the ratio 3:5. If 8 is added to both the numbers, the ratio becomes 2:3. What is the larger number?
3-in-1 protection for moms-to-be helps protect baby too.
Lets call the numbers p and q (for a change)
The first ratio means 5p = 3q
This may look the wrong way round, but remember p is the smaller number so needs the bigger multiplier to become equal
The second Ratio means 3(p+8) = 2(p+8) [using the same logic)
3p + 24 = 2q + 16 [Multiplying out the brackets]
Now we have got two equations, there are different ways to combine them
I’m going to do this by substitution
Simplify the 2nd to give 3p + 8 = 2q and then q = 3/2 * p + 4
(By taking 16 from both sides then dividing by 2)
5p = 3(3/2 * p + 4) = 9/2 + p + 12 - Substituting our statement for q into the first equation)
The 1/2 is a bit awkward so I will multiply through by 2
10p = 9p + 24
Take 9p from both sides
p = 24
Use this value of p and the first ratio
3q = 5 * 24 = 120.
so q = 40
We have a solution now; p=24, q= 40. But I always like to check the answer against the question
p:q = 24:40 = 3:5 - good
Answer:
7:5
Explanation:
changes to 7 Anpadh 5 in that the number 57