WRITTEN PROBLEMS INVOLVING EQUIVALENT RATIO

Problem Solving

Q(i):- The ratio of profit to cost price on sales at DeeDee's is 3 : 5

Find the cost price of a skirt if the sales profit is £30?

First lets look at the question:-

First we have the ratio of profit to cost so we'll write this in ratio format P : C

Next the question tells us that it is in the ratio of 3 : 5

We have been asked to find the cost price and we've been told the profit is £30

A(i):-Therefore we can write the information we've been given as follows;

P : C

3 : 5

30 : ?

The 3 has turned into 30 so we will have to divide;

30 ÷ 3 = 10 (Now we must multiply the 5 X 10)

10 X 5 = 50

Therefore the cost price for the skirt is £50

 

(ii):- A type of concrete requires a mixture of sand, cement and grit in the ratio 4 : 1 : 2 , if 14 buckets of sand are used what are the quantities of cement and grit required?

We have the ratio of sand, cement and grit, so let's write this in ratio format

S : C : G

Next the question tells us these items are in the ratio of 4 : 1 : 2

We are told that 14 buckets of sand are used

We've been asked to find the quantities of cement and grit required

A(ii):-Therefore we can write the information we've been given as follows;

S : C : G

4 : 1 : 2

14 : ? : ?

We've went from 4 to 14 so we'll divide 14 ÷ 4 = 3.5(now we must multiply the 1 and the 2 by 3.5)

1 X 3.5 = 3.5 (cement)

2 X 3.5 = 7 (grit)

So to answer the question how much cement and grit is needed we see there is;

Cement 3.5 buckets and

Grit 7 buckets required.

 

 

NOW TO DIVIDE THE QUANTITIES IN A GIVEN RATIO:-

Q(i):- Divide £400 between John and Simon in the ratio 1 : 4

A(i):- J : S

          1 : 4 = 5 parts

JOHN: 1/5 x 400 = £80 that is (400 ÷ 5 = 80)

SIMON: 4/5 x 400 = £320 that is ( 400 ÷ 5 = 80 then multiply the 80 x 4 = 320)

JOHN gets £80 and SIMON gets £320.

 

Q(ii):- The three angles in a triangle are in ratio 1 : 2 : 3, Find the size of each of the angles?

A(ii):- All the angles in a triangle add up to 180 degrees.

1 : 2 : 3 = 6 parts

Angles: the first angle we will look at is the 1 part out of the 6 parts, so as a fraction it would be 1/6 (one sixth)- therefore it will be 1/6 of the 180 degrees.

180 ÷ 6 = 30 degrees

The next angle is represented by the 2 parts out of the 6 parts, so as a fraction it would be 2/6(two sixths)which is equivalent to a 1/3(one third) - therefore this angle will be1/3 of the 180 degrees.

180 ÷ 3 = 60 degrees

The last angle is represented by the 3 parts out of the 6 parts, so as a fraction it would be 3/6 (three sixths) which is equivalent to a 1/2 ( a half ) - therefore this angle will be 1/2 of the 180 degrees.

180 ÷ 2 = 90 degrees

As an extra measure to check the sum of the degrees add them up;

30 + 60 + 90 = 180

Therefore the calculations are correct.

The size of the angles are 30 , 60 , and 90 degrees.

 

Q(iii):- A piece of rope is 60cm long and is cut into three pieces in the ratio 4 : 1 : 5

Find the length of the shortest piece?

A(iii):- 4 : 1 : 5 = 10 parts

The shortest piece is represented by the 1 part;

Therefore 1/10 x 60 = 6cms

The shortest piece is 6cms in length

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Comments 5 comments

empeen profile image

empeen 6 years ago from India

I cant understand why are you doing this?


t.elia profile image

t.elia 6 years ago from Northern Ireland Author

For further help follow the link in the hub "Let me solve your maths problems". Assistance can be found for

Bodmas

HCF

LCM

Prime and Composite numbers

Square Root

Cube Root

Place Values

Expanded Notation

Rounding off Numbers

Writing numbers as a product of their Prime Numbers


dingo 6 years ago

Brillant maths site really helpful


t.elia profile image

t.elia 6 years ago from Northern Ireland Author

Thankyou very much dingo your comments are really appreciated


t.elia profile image

t.elia 3 years ago from Northern Ireland Author

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