CEKENAS END OF TERM ONE EXAMINATION, 2025 121/1 MATHEMATICS PAPER 1

CEKENAS END OF TERM ONE EXAMINATION, 2025
Kenya Certificate of Secondary Education (K.C.S.E)
121/1
MATHEMATICS
PAPER 1
TIME: 2½ HOURS
INSTRUCTIONS TO CANDIDATES
1. This paper consists of two sections I and II.
2. Answer all the questions in section I and only five in questions from section II.
3. Show all steps in your calculations, giving your answers at each stage.
4. Marks may be given for correct working even if the answer is wrong.
5. Non-programmable silent electronic calculators and KNEC mathematical tables may be used expect
when stated otherwise
SECTION I
Answer all the questions in this question
1. Evaluate.
(3marks)
−2
  3 5 2 
 1 −  

  7 8 3 
3
5 4
1
 + 1  of 2 
7 7
3
4
2. Four years ago, a father was thrice as older as his son. In five years’ time, the sum of their ages
will be 42 years. Find how old the father was, when the son was born.
(3marks)
3. Use the prime factors of 1936 and 1728 to evaluate.