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1. Calculate Upper and lower bound

2.(100.0)/(50.0-40.0)^2

Formula UB=(UB-LB)^2 LB=(LB-UB)^2
2. (Original post by zx0xc0)
Calculate Upper and lower bound

2.(100.0)/(50.0-40.0)^2

Formula UB=(UB-LB)^2 LB=(LB-UB)^2
What you've written doesn't make any sense. If you want upper and lower bounds for an expression, you need to know the degree of accuracy to which each of the values is given, and you haven't provided that information.

3. To be fair to OP, these questions usually imply that the numbers have been quoted in such a way that one place is missing. In this case,
for the UB, the numerator needs to be as big as possible and the denominator as small as possible.

Hence

BTW, at GCSE (IMHO) trying to learn formula such as Formula UB=(UB-LB)^2 LB=(LB-UB)^2 is unnecessary, you are far better thinking about the fraction involved and about how you can make the UB (top-big bottom-small) or the LB (top-small bottom-big). Formulae are useful but sometimes serve as a barrier to understanding where formulae are invented to handle every possible situation.

Working for the LB is similar.

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