How to Take This Test

25 questions in 15 minutes is the Tier 1 Maths pace of about 36 seconds a question, so the full year-by-year working will not fit every time. Have the quick tools ready: the yearly multipliers such as 1110\frac{11}{10} for 10% and 2120\frac{21}{20} for 5%, 2R+R21002R + \frac{R^2}{100} for two years of CI, PR21002\frac{P R^2}{100^2} for the CI and SI difference, and difference ÷ earlier amount for the rate. SI and CI questions are mixed, so check which one each question is about before you start.

  • Use a timer and finish in one go, with your notes closed.
  • Score it the exam way: +2 for a right answer, −0.50 for a wrong one, 0 for a skip.
  • Leave the long ones (three instalments, three-year differences) for the end. One of them can take the time of three quick SI questions.
  • Open the explanations only when the 15 minutes are over.

Your score. Take 2 marks for each right answer and subtract 0.5 for each wrong one; the total is out of 50. So 20 right, 3 wrong and 2 left blank gives 40 − 1.5 = 38.5.

Score (out of 50) What to do next
40 or more This chapter is done. Go through the PYQ Practice Sets now and then to keep it fresh.
30 to 39.5 Look at your wrong answers. If they were amount-for-interest or one-year-short slips, read the questions more slowly; if they were CI − SI or instalment questions, redo the quiz in CI vs SI, Splitting Sums and Instalments.
20 to 29.5 You know the methods but are slow with them. Go through Shortcuts & Speed Methods, mainly the multipliers and the CI − SI rule, then Practice Sets 1 and 2, and take this test again in a few days.
Below 20 Start again from Simple Interest, then Compound Interest and CI vs SI, Splitting Sums and Instalments, before more timed work.

The tag on each question names its topic. CI − SI, CI and SI on one sum, equal-amount splits and CI instalments are in CI vs SI, Splitting Sums and Instalments; the rest are in Simple Interest or Compound Interest, as the tag says.

More than 3 wrong usually means you were rushing. On guessing, Chapter 0 works it out: in Tier 1 a blind guess is very slightly in your favour on average (about +0.125 marks), and once you can rule out even one option, a guess is clearly worth taking.