Friday Revision

The fourth, fifth and sixth terms of a geometric sequence are 7.5, 3.75 and 1.875 respectively. The sum of the first and second terms in the geometric sequence is:

A scientist observed that the population of a specific bird species is decreasing by 17% each year and that at the beginning of 2016, there were 483 birds. Predict the number of birds remaining at the beginning of 2021.

Use the recursive rule 𝑡n+1 = 0.65𝑡n, t1 = 120 to complete the following. Calculate the fourth term rounded to the nearest whole number.

Geometric Question.
t3 = 90, t5 = 57.6. What is the first term (round answer to nearest whole number)?

P and Q are two points on the Earth’s surface with coordinates (45N, 10W) and (15N, 10W) respectively. Calculate the distance between P and Q to the nearest kilometer.

Calculate the distance between he following points to the nearest kilometer. (10N, 45E) and (25S, 45E)

Is Thursday Island (10S, 142E) closer to the South or North Pole?

• North

• South

What number is missing?

Monthly sales figures for a company between January 2016 and December 2018 were used to calculate the following seasonal indices. The missing seasonal index for November is:

What is the difference between Arithmetic and Geometric Sequences?

• Arithmetic - common difference, with addition/subtraction added to each term. Geometric - common ratio, with multiplication/division to each term.

• Arithmetic - common difference, with multiplication/division added to each term. Geometric - common ratio, with addition/subtraction to each term.