Bala had 9 stickers
You could set this up as a equation. Because there was a total of 26 you would for sure put =26. Next you are told Alvin has 8 MORE than Bali, therefore you would be adding the unknown value of Bala by 8. This could be represented as x+8=26. Now that you have x added to 8 you need to add another x to the equation to fully represent the problem since Alvin has 8 more stickers than Bala does. The new equation would become 2x+8=26.
You must now isolate x by first subtraction 8 from both sides which will leave you with 2x=18. Then you divide on both sides by 2 and will leave you with x=9
X: earn per hour during the week
y: earn per hour during the weekend
13x + 14y = 250.90
15x + 8y = 204.70
Multiply the first equation by 4 and the second equation by 7
52x + 56y = 1003.6
105x + 56y = 1432.90
Subtract the first equation from the second:
53x = 429.30
x = 429.30/ 53
x = 8.10
Solve any of the equation for y:
15x + 8y = 204.70
y = [204.70 - 15(8.10)]/8 = 10.40
y - x = 10.40 -8.10 = 2.30
Answer: she earns $2.30 per hour more during the weekend than during the week.