We are given the problem of finding the upper and lower bounds of $1300 \div 45$, where both numbers are correct to 2 significant figures. The final answer must be correct to 2 significant figures.

ArithmeticBoundsSignificant FiguresDivisionEstimationError Analysis
2025/4/21

1. Problem Description

We are given the problem of finding the upper and lower bounds of 1300÷451300 \div 45, where both numbers are correct to 2 significant figures. The final answer must be correct to 2 significant figures.

2. Solution Steps

First, we determine the upper and lower bounds of each number.
Since 1300 is given to 2 significant figures, it is in the hundreds. Thus, the accuracy is to the nearest
1

0. So, $1300 = 1.3 \times 10^3$. The uncertainty is $\frac{1}{2} \times 10 = 5$.

Therefore, the upper bound of 1300 is 1300+50=13501300 + 50 = 1350, and the lower bound is 130050=12501300 - 50 = 1250.
Since 45 is given to 2 significant figures, it is in the tens. Thus, the accuracy is to the nearest

1. So the uncertainty is $\frac{1}{2} \times 1 = 0.5$.

Therefore, the upper bound of 45 is 45+0.5=45.545 + 0.5 = 45.5, and the lower bound is 450.5=44.545 - 0.5 = 44.5.
To find the upper bound of the division, we divide the upper bound of the numerator by the lower bound of the denominator:
Upper bound =135044.530.3370786530.3= \frac{1350}{44.5} \approx 30.33707865 \approx 30.3.
To find the lower bound of the division, we divide the lower bound of the numerator by the upper bound of the denominator:
Lower bound =125045.527.4725274727.5= \frac{1250}{45.5} \approx 27.47252747 \approx 27.5.
We are asked to correct the bounds to 2 significant figures.
Upper bound to 2 sf: 30
Lower bound to 2 sf: 27
However, the question asks for the answer "correct to 2 significant figures".
We recalculate the upper and lower bounds with more precision, as rounding intermediate values could introduce larger errors.
Upper bound =135044.530.3370786516853930= \frac{1350}{44.5} \approx 30.33707865168539 \approx 30
Lower bound =125045.527.4725274725274727= \frac{1250}{45.5} \approx 27.47252747252747 \approx 27

3. Final Answer

Upper bound: 30
Lower bound: 27

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