Question

Monday: 10 apples and 5 bananas cost £4.20 Friday: 8 apples and 10 bananas cost £5.40 Find the cost of each - with an explanation please and thank you so much

Answer 1

Answer:

An apple costs £0.25

A banana costs £0.34

Step-by-step explanation:

Let a be apples and b be bananas.

10a+5b=4.2

8a+10b=5.4

Solve for a:

10a+5b=4.2

Subtract 5b from both sides

10a=4.2-5b

Subtract 4.2 from both sides

10a-4.2= -5b

Multiply both sides by -1

-10a+4.2=5b

8a+10b=5.4

Subtract 10b from both sides

8a=5.4-10b

Subtract 5.4 from both sides

8a-5.4= -10b

Multiply both sides by -1

-8a+5.4= 10b

Divide both sides by 2

-4a+2.7=5b

Combine equations:

-4a+2.7= -10a+4.2

Add 10a to both sides

6a+2.7=4.2

Subtract 2.7 from both sides

6a=1.5

Divide both sides by 6

a=0.25

An apple costs £0.25

Solve for b:

10a+5b=4.2

Subtract 10a from both sides

5b= -10a+4.2

Subtract 4.2 from both sides

5b-4.2= -10a

Multiply both sides by -1

-5b+4.2=10a

8a+10b=5.4

Subtract 8a from both sides

10b= -8a+5.4

Subtract 5.4 from both sides

10b-5.4= -8a

Divide both sides by 4

2.5b-1.35= -2a

Multiply both sides by 5

12.5b-6.75= -10a

Multiply both sides by -1

-12.5b+6.75=10a

Combine equations:

-12.5b+6.75= -5b+4.2

Add 12.5b to both sides

6.75=7.5b+4.2

Subtract 4.2 from both sides

2.55=7.5b

7.5b=2.55

Divide both sides by 7.5

b=0.34

A banana costs £0.34

If you would like to check and see if it is true, (I already checked, it is) you can use the formulas I gave at the start of the explanation.

10a+5b=4.2

8a+10b=5.4

a=0.25

b=0.34