Stage 9 - Q1 - 2 marks
Calculate exactly.
Hint
A negative power is a reciprocal.
Stage 9 - Q2 - 2 marks
Calculate exactly.
Hint
The number of negative factors determines the sign.
Stage 9 - Q3 - 3 marks
Calculate exactly.
Hint
The divisor can be made an integer without changing the quotient.
Stage 9 - Q4 - 3 marks
Increase 190 by 11%, then by 13%.
Hint
Multiply the two multipliers; do not add the percentages.
Stage 9 - Q5 - 4 marks
Decrease 400 by 6% per year for 3 years. Give 2 d.p.
Hint
Retain calculator precision between years.
Stage 9 - Q6 - 4 marks
Decrease 450 by 8% per year for 3 years. Give 2 d.p.
Hint
Retain calculator precision between years.
Stage 9 - Q7 - 5 marks
A positive multiple of 0.1 rounds to 28 to the nearest 1. Find the smallest and largest allowed original values.
Hint
The allowed original values have a stated spacing.
Stage 9 - Q8 - 5 marks
A positive measurement rounds to 68 to the nearest 1. Write its error interval.
Hint
Use half the rounding unit on either side.
Stage 9 - Q9 - 5 marks
Find the single overall percentage change equivalent to a 21% increase followed by a 16% decrease.
Hint
Compare the combined multiplier with 1.
Stage 9 - Q10 - 3 marks
A positive continuous quantity is displayed as 120 after rounding to the nearest 10. Its true value then rises by 20% and falls by 10%. Find the exact interval for the final value, assuming no intermediate rounding.
Hint
A positive multiplier preserves the order and endpoint inclusion.