A pen costs npence and a ruler costs15pence more than a pen.I paid 2.47pounds for 7pens&4rulers.Find n. ?

Question

A pen costs npence and a ruler costs15pence more than a pen.I paid 2.47pounds for 7pens&4rulers.Find n. ?

Answer 1

Cost of pen in pence (n):

7n + 4(n + 15) = 247

7n + 4n + 60 = 247

11n = 187

n = 17

Cost of ruler in pence:

= 17 + 15

= 32

Answer: 17 pence for each pen; 32 pence for each ruler

Proof (Total cost: 2.47 pounds):

= (7 pens * 0.17 pounds) + (4 rulers * 0.32 pounds)

= 1.19 pounds + 1.28 pounds

= 2.47 pounds

Answer 2

Hi from the U.S., my brother lives in England (Lincoln)

Always begin by defining your unknown. In this problem, you are told that a pen costs n pence. Next define your other unknowns in terms of n.

Let n = the cost of a pen

Then n + .15 = the cost of a ruler

Fill in the cost for 7 pens + 4 rulers --->

7(n) + 4(n + .15)

Set your above expression equal to the given total

7(n) + 4(n + .15) = 2.47

Distribute and simplify

7n + 4n + .60 = 2.47 pounds

11n + .60 = 2.47

Subtract .60 from both sides of the = sign

11n = 1.87

Divide both sides by 11

n = .17

Answer:

n = .17 (cost of a pen)

n + .15 = .32 (cost of a ruler)

CHECK:

7(.17) + 4(.32) = 1.19 + 1.28 = 2.47

The answer checks out, it's correct