Mathematics 0580 · IGCSE · Sequences

Sequences — practice question

On Monday, Ankuri sent this text message to two friends. "Today is Day Number 1. Tomorrow, please add 1 to the Day Number and send this text message to two friends." Every friend who gets a text message carries out the instructions.
(a)[4]

Complete the table by filling in the missing entries.

(b)[1]

Write down an expression giving the number of text messages sent on Day Number $n$.

(c(i))[2]

Show that her statement is correct.

(c(ii))[2]

Complete the statement. By the end of Day Number 5, the total number of text messages sent is ................. which is equal to $2^k - 2$ where $k = .................$.

(c(iii))[1]

Write down an expression for the total number of text messages sent by the end of Day Number $n$.

(c(iv))[1]

Find the Day Number at which the total number of text messages sent by the end of the day is 1022.

Worked solution & mark scheme

This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: Sequence doubled accurately through to $128$

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