Simple math problem could indicate your religious beliefs.

[Tiberius]

Sorry, but I still don't understand. You said:

The question is worded so that you may wrongly assume that;

x+y=$110

(bolding mine)

Yet there is absolutely nothing wrong with this assumption...it's correct. In the question, x + y = $110 is clearly defined at the beginning. This equation has nothing to do with the (wrong) assumption that the bat costs $100.

[Phil]

Very simple mathematics:

x = Cost of a ball.
y = Cost of a bat.

This gives us the following two equations:

x + y = $110 (1)
y = x + $100 (2)

Substitute (2) into (1):

x + (x + $100) = $110

So:

2x + $100 = $110

So:

2x = $10

So:

x = $5

Can't we just start at the bold equation since the question doesn't care how much the bat costs. It is just asking what x is when x + (x + 100) = 110.

---

I hate maths.

How do you think I feel after 3 damn years of Calculus.

[Gambit]

I'm pretty sure I'm numerically dyslexic or some shit, because that “simple” equation just fried my last brain cell. That's it, I'm going back to school to learn mathematics. pfft.

[Tiberius]

Can't we just start at the bold equation since the question doesn't care how much the bat costs. It is just asking what x is when x + (x + 100) = 110.

Sure, you can do that, but some people might be a bit confused as to how you got that equation in the first place. With linear equations, the standard way to solve them is to write out all the details of the question as simple equations first, and then combine them, cancelling out variables as you go.

[Faith No More]

Can't we just start at the bold equation since the question doesn't care how much the bat costs. It is just asking what x is when x + (x + 100) = 110.

You need the two equations ubove that to get to the bold eqution.

[Napoléon]

How do you think I feel after 3 damn years of Calculus.

I feel your pain bro.

[Welsh cake]

Ah, but where would you be without it?

Arguably better off.

=.=