7 t-shirts and 5 hats costs £32. 3 t-shirts and 4 hats costs £23.
Find the cost of a t-shirt.
Find the cost of a hat

Step-by-step explanation:

Let x be the cost of t-shirts

and

y be the cost of hats

Then,

7x + 5y = £32 (i)

And

3x + 4y = £23 (ii)

Now,

Solving (i) and (ii) by Elimination method, we get -

[ 7x + 5y = £32 ] × 4

[ 3x + 4y = £23 ] × 5

= 28x + 20y = £128

15x + 20y = £115

- - -

13x = £13

x = £13/13

Now, substituting the value of x on equation (i)

= 7(£1) + 5y = £32

= £7 + 5y = £32

= 5y = £32 - £7

= 5y = £25

y = £25/5

Hence,

The cost of t-shirt is £1

and

the cost of hats is £5.

answer: all of the odd numbers were opened

the first person was the one that was opening all of the lockers. since one is odd, this causes all of the odd number lockers to be opened in the end.