CIE Mathematics Paper-1: Specimen Questions 26 - 27 of 175

Question number: 26

Short Answer Question▾

Write in Short

Look at the sequence of numbers 7,11,15,19,

(a) Write down the next number in the sequence.

(b) Find the 10th number in the sequence.

(c) Write an expression, in terms of n, for the nth number in the sequence.


Here, sequence is 7,11,15,19,

(a) Here, these numbers are odd numbers and also this sequence is having the numbers like:


So, here bold numbers are not in sequence, so after 19 there will be 23.

(b) Here, further sequence is like: 7,11,15,19,23,27,31,35,39,43

So, 43 will be the 10th number in the series.

(c) Expression in terms of n of sequence 7,11,15,19,:[7+(n1)×4], where nN .

  • So, first term will get by: 7+(11)×4=7+0=7.
  • Second term will get by: 7+(21)×4=7+4=11.
  • Third term will get by: 7+(31)×4=7+2×4=7+8=15 and so on.

Question number: 27

Essay Question▾

Describe in Detail

(a) A balloon man has 30 balloons. In which 8 balloons are pink, 12 balloons are white and 10 balloons are blue. One balloon is selected randomly. So, find the probability of not getting pink balloon.


Here, There are total 30 balloons. 8 are pink, 12 are white and 10 are blue.

So, probability of pink balloons is: 830=415

Probability of white balloons is: 1230=25

Probability of blue balloons is: 1030=13

Now, probability of not getting pink balloon = probability of getting white and blue balloons: 25+13=6+515=1115.


Probability of not getting pink balloon = 1probabilityofgettingpink=1415=15415=1115.