For this case, the first thing we must do is define variables.
We have then:
t: cost of the torch
b: cost of the battery
The cost of both items in £ is given by:
[tex] 10-4.84 = 5.16 [/tex]
Therefore, we have the following equation:
[tex] t + b = 5.16 [/tex]
Then, we know that:
The torch costs eleven times as much as the battery.
[tex] t = 11b [/tex]
Substituting equation two in the equation we have:
[tex] 11b + b = 5.16 [/tex]
Clearing the value of b we have:
[tex] 12b = 5.16 [/tex]
[tex] b = \frac{5.16}{12} [/tex]
[tex] b = 0.43 [/tex]
Answer:
The cost of the battery is 0.43 £
