Skip to content
MathsGenie logo
Quick links
Open app

Course home

  1. A Level
  2. Maths AQA
  3. Question bank

1.7.5 Geometric sequences and series (A-level only)

EasyMedium
1234567891011121314151617181920212223242526272829303132333435363738394041424344
Question 40

An industrial vat used for fermentation is being cleaned, and the primary supply is shut off. At the moment of shut-off, the vat contains 450 litres of liquid. However, residual fluid continues to drip from the overhead processing coils into the vat.

In the first minute after the supply is shut off, 800 millilitres of liquid drips into the vat. In each subsequent minute, the volume of liquid dripping into the vat reduces by 16%.

During the n n\,nth minute after the supply is turned off, the volume of liquid dripping into the vat is Wn W_n\,Wn​ millilitres.

a.

Find W2W_2W2​.

[1]
b.

Explain why Wn=A×0.84n−1W_n = A \times 0.84^{n-1}Wn​=A×0.84n−1 and state the value of AAA.

[2]
c.

Find the total increase in the volume of liquid in the vat 15 minutes after the supply is shut off. Give your answer to the nearest millilitre.

[3]
d.

Assuming no liquid is lost or added from other sources, calculate the maximum possible total volume of liquid in the vat.

[3]
e.

After a significant period of time has passed, the dripping has ceased. Give two reasons why the final volume of liquid in the vat might not reach the theoretical maximum calculated in part (d).

[2]

1.7.5 Geometric sequences and series (A-level only) Questions

  1. A Level
  2. /Maths
  3. /1.7.5 Geometric sequences and series (A-level only)