Time = Distance / Speed = 240 km / 80 km/h = 3 hours.

Percentage error = (Uncertainty / Measured value) * 100 = (0.01 / 5.67) * 100 ≈ 0.176%.

Total length = 3 * 1.20 m = 3.60 m. The uncertainty for 3 tables = 3 * 0.02 m = 0.06 m.

The range of possible true values is from 25.0 - 0.5 to 25.0 + 0.5, which is 24.5 °C to 25.5 °C.

Minimum possible volume = Measured volume - Uncertainty = 250.0 mL - 1.0 mL = 249.0 mL.

Speed = Distance / Time = 150 km / 2.5 h = 60 km/h.

Distance = speed × time = 60 km/h × 3 h = 180 km.

The measurement 150.0 cm has 4 significant figures because the trailing zero after the decimal point is significant.

The leading zeros are not significant. Therefore, 0.00456 has 3 significant figures.

Absolute error = |Measured value - True value| = |12.30 - 12.5| = 0.2 cm.

The leading zeros are not significant. Therefore, 0.050 kg has 2 significant figures.

Circumference = π * diameter = π * 10.0 cm ≈ 31.4 cm. Uncertainty in circumference = π * 0.1 cm ≈ 0.314 cm.

Let the original price be x. Then, x - 0.2x = 40, which gives 0.8x = 40. Thus, x = 40 / 0.8 = $50.

Circumference = 2πr = 2 × 3.14 × 7 cm = 43.96 cm.

The third angle can be found by subtracting the sum of the other two angles from 180 degrees: 180 - (50 + 70) = 60 degrees.

Let the numbers be x and y. We have x + y = 30 and x - y = 10. Solving these gives x = 20 and y = 10.

Relative error = (Uncertainty / Measured value) * 100 = (0.5 / 50.0) * 100 = 1%.

Maximum possible mass = Measured mass + Uncertainty = 2.50 kg + 0.05 kg = 2.55 kg.

The number 100.0 has 1 decimal place, so the answer should also be rounded to 1 decimal place.

The number with the least decimal places is 0.3 (1 decimal place), so the answer should be rounded to 1 decimal place.

The result of 3.4567 + 2.1 is 5.5567. However, since 2.1 has only 2 significant figures after the decimal, the result should be rounded to 5.6, which has 3 significant figures.

The number 3.4567 has 4 significant figures. The leading digit is not counted as significant.

To find x, subtract 5 from both sides: 3x = 20 - 5 = 15. Then divide by 3: x = 15 / 3 = 5.

The term 2.1 × 10^2 has 2 significant figures, so the final answer should be rounded to 2 significant figures.

Substituting x = 2 into the equation gives 5(2) + 3y = 15, which simplifies to 10 + 3y = 15. Thus, 3y = 5, and y = 5/3.

2.5 has 2 significant figures and 3.456 has 4 significant figures. The result should be rounded to 2 significant figures, giving 8.6.

Adding 7 to both sides gives 3x = 9. Dividing by 3 gives x = 3.

The number 3.0 has 2 significant figures, so the result should also be reported with 2 significant figures.

Rounding 0.006789 to three significant figures gives 0.00679.