|
Activities | Logic Q's | Estimation Q's | |
| Long Division | Index |
If two apples plus three pears costs 130 pence and four apples plus two pears cost 140 pence, how much does one apple plus one pear cost?
Write out the question in mathematical format. A stands for apples and P for pears.
2A + 3P = 130
4A + 2P = 140
Now find a way to remove either the variable A or P from the equations to leave you the cost of a certain number of only one type of fruit.
50 pence
Writing out the question in mathematical format we have:
Eqn 1: 2A + 3P = 130
Eqn 2: 4A + 2P = 140
A stands for apples, P for pears and the figure on the right of the equals sign is the cost of the items in pence.
We now need to remove either the variable A or P from the equations to leave you the cost of a certain number of only one type of fruit. This can be done by multiplying equation 1 by 2.
Eqn 1 * 2: 4A + 6P = 260 (every number multiplied by 2)
Now we can subtract eqn. 2 from the multiplied eqn.1 (Be sure to keep each number on the correct side of the equals sign.)
Eqn. 1 *2 - Eqn 2:
(4A - 4A) + (6P - 2P) = (260 - 140)
=> 0 + 4P = 120
=> P = 30
We now have the cost of one pear; 30 pence. Knowing this we can substitute the P in equation 1 for the figure 30 and thus work out the cost of one apple.
Eqn 1. 2A + 3P = 130
=> 2A + 3*30 =130
=> 2A + 90 =130
=> 2A = 130 - 90
=> 2A = 40
=> A = 20
i.e. the cost of one apple costs 20 pence.
The cost of one apple and one pear is therefore:
20 + 30 = 50 pence.
Any requests? E-mail them to WebMaster@IntellectualLoafing.com
| } |
Activities | Logic Q's | Estimation Q's | Please send all comments to WebMaster@IntellectualLoafing.com |
| Long Division | Index |
