Advertisements
Advertisements
प्रश्न
In a test, +3 marks are given for every correct answer and –1 mark are given for every incorrect answer. Sona attempted all the questions and scored +20 marks though she got 10 correct answers.
- How many incorrect answers has she attempted?
- How many questions were given in the test?
Advertisements
उत्तर
i. Total marks scored by Sona = 20
Total correct answers = 10
∴ Marks for correct answers = 10 × 3 = 30
but she got 20 marks.
∴ Marks for incorrect answers = 20 – 30 = –10
–1 mark is given for every incorrect answer.
ii. Total correct answers = 10
Total incorrect answers = 10 ...(From (i) part)
∴ Total questions given in the test = 10 + 10 = 20
APPEARS IN
संबंधित प्रश्न
Find the product, using suitable properties:
7 × (50 − 2)
Find the product, using suitable properties:
(− 17) × (− 29)
Find the following product: (– 25) × 37 × 4
Find the following products: (– 20) × (– 2) × (– 5) × 7
Find (– 23) × 48
Find 52 × (– 8) + (–52) × 2
If Δ is an operation such that for integers a and b we have a Δ b = a × b – 2 × a × b + b × b (–a) × b + b × b then find 4 Δ (–3) Also show that 4 ∆ (–3) ≠ (–3) ∆ 4.
The given table shows the freezing points in °F of different gases at sea level. Convert each of these into °C to the nearest integral value using the relation and complete the table,
`C = 5/9 (F - 32)`
| Gas | Freezing Point at Sea Level (°F) |
Freezing Point at Sea Level (°C) |
| Hydrogen | –435 | |
| Krypton | –251 | |
| Oxygen | –369 | |
| Helium | –458 | |
| Argon | –309 |
A green grocer had a profit of ₹ 47 on Monday, a loss of ₹ 12 on Tuesday and loss of ₹ 8 on Wednesday. Find his net profit or loss in 3 days.
If Δ is an operation such that for integers a and b we have a Δ b = a × b – 2 × a × b + b × b (–a) × b + b × b then find (–7) Δ (–1). Also show that (–7) Δ (–1) ≠ (–1) Δ (–7).
