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Question
primary 6 | Maths
| Algebra
3 Answers Below
Anyone can contribute an answer, even non-tutors.
please help
Date Posted: 4 years ago
Views: 246
Answer for 1st question = 6
thankuu
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Let x be the number of boys at first, which means total savings of boys at first is
(X times $2.80)
After Tom joins with $4.20, the following changes happen:
- the average savings becomes $3
- the number of boys become (x + 1)
- the total savings become [(X x $2.80) + $4.20]
Hence,
[(X x 2.80) + 4.20] = (X + 1) x 3
2.8X + 4.20 = 3X + 3
1.20 = 0.2X
X = 6
So total of boys at the start is 6.
(X times $2.80)
After Tom joins with $4.20, the following changes happen:
- the average savings becomes $3
- the number of boys become (x + 1)
- the total savings become [(X x $2.80) + $4.20]
Hence,
[(X x 2.80) + 4.20] = (X + 1) x 3
2.8X + 4.20 = 3X + 3
1.20 = 0.2X
X = 6
So total of boys at the start is 6.
done
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Hope this helps
Date Posted:
4 years ago
For the bottom question, we know each plant’s height in terms of e and they are:
> (2e - 3)
> (4e + 1)
> (e + 2)
So, to find out the total height of all 3, you need to add all of them up:
(2e - 3) + (4e + 1) + (e + 2)
= 2e + 4e + e - 3 + 1 + 2
= 7e
A) total height of plants = 7e
To find out the height of the tallest plant, you’d need to find out what e is.
Since they told you average height of 3 plants is 35cm, so you know the total height of all 3 plants = 35cm x 3 = 105cm.
From part (A),
total height of all plants
= 7 e which is also 105cm.
7e = 105cm
So e = 15cm
So now, you can find out the height of each plant:
> (2e - 3) = 30 - 3 = 27
> (4e + 1) = 60 + 1 = 61
> (e + 2) = 15 + 2 = 17
B) So tallest plant is 61cm.
> (2e - 3)
> (4e + 1)
> (e + 2)
So, to find out the total height of all 3, you need to add all of them up:
(2e - 3) + (4e + 1) + (e + 2)
= 2e + 4e + e - 3 + 1 + 2
= 7e
A) total height of plants = 7e
To find out the height of the tallest plant, you’d need to find out what e is.
Since they told you average height of 3 plants is 35cm, so you know the total height of all 3 plants = 35cm x 3 = 105cm.
From part (A),
total height of all plants
= 7 e which is also 105cm.
7e = 105cm
So e = 15cm
So now, you can find out the height of each plant:
> (2e - 3) = 30 - 3 = 27
> (4e + 1) = 60 + 1 = 61
> (e + 2) = 15 + 2 = 17
B) So tallest plant is 61cm.
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