Mathematics · solved example
Simplify: 36 × 12 ÷ 9 + 15.
- 61
- 63Correct
- 65
- 59
Solution
36 × 12 = 432, ÷ 9 = 48, + 15 = 63.
RRB NTPC | Computer Based Test 1
RRB NTPC CBT 1: Mathematics sprint (20 questions)
A short, single-clock Mathematics sectional at CBT 1 pace: 20 original questions with one third negative marking, for a quick 18-minute drill of the arithmetic that decides the section.
Before you start
- One clock of 18 minutes for 20 questions, matching the roughly 54 seconds a question that CBT 1 allows.
- Every question carries one mark and one third of a mark is deducted for a wrong answer. Unanswered questions carry no penalty.
- No calculator is provided, exactly as in the real CBT 1.
Sections in this test
| Section | Questions |
|---|---|
| MathematicsMathematics | 20 |
Sample questions with worked solutions
A few questions from this test, with the answer key and the method behind it. The full set of 20 runs under a timer, and every solution is on the analysis screen once you submit.
Mathematics · solved example
On selling an article for Rs 350, a shopkeeper loses 12.5%. Find its cost price.
- 420
- 390
- 400Correct
- 380
Solution
A 12.5% loss means 350 = 87.5% of cost, so cost = 350 ÷ 0.875 = 400.
Mathematics · solved example
An article bought for Rs 250 is sold for Rs 300. Find the profit percent.
- 20%Correct
- 25%
- 15%
- 18%
Solution
Profit = 50 on a cost of 250, so profit percent = 50/250 × 100 = 20%.
Mathematics · solved example
A can do a work in 10 days and B in 15 days. Working together, in how many days will they finish it?
- 7
- 6Correct
- 8
- 5
Solution
Together they do 1/10 + 1/15 = 1/6 of the work a day, so it takes 6 days.
Mathematics · solved example
The speed of a boat in still water is 10 km/h and the stream flows at 2 km/h. Find the upstream speed of the boat.
- 6
- 8Correct
- 12
- 10
Solution
Upstream speed = still-water speed − stream speed = 10 − 2 = 8 km/h.
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How this test is marked
Correct answer
+1
Wrong answer
-0.3333
Unanswered
0
Because a blank carries no penalty, guessing only pays when you can eliminate at least two options. The analysis screen after the test shows you exactly where guessing cost you marks.