GAT Quantitative Reasoning 3 — Questions and Answers
Question 1: If 3x + 7 = 22, what is the value of 6x + 14?
- 30
- 44 (Correct answer)
- 37
- 52
Correct answer: 44
From 3x + 7 = 22, we get 3x = 15. The expression 6x + 14 = 2(3x + 7) = 2 × 22 = 44.
Rather than solving for x first, recognize that 6x + 14 = 2(3x + 7). Since 3x + 7 = 22, then 6x + 14 = 2 × 22 = 44. This algebraic shortcut saves time. Alternatively: 3x = 15, so x = 5, then 6(5) + 14 = 30 + 14 = 44.
Question 2: A store offers a 20% discount on a shirt priced at 150 SAR. After the discount, a 15% VAT is added. What is the final price?
- 120 SAR
- 138 SAR (Correct answer)
- 127.50 SAR
- 142.50 SAR
Correct answer: 138 SAR
After 20% discount: 150 × 0.80 = 120 SAR. After 15% VAT: 120 × 1.15 = 138 SAR.
Step 1: Calculate the discounted price. 20% of 150 = 30, so discounted price = 150 - 30 = 120 SAR. Step 2: Apply 15% VAT on the discounted price. 15% of 120 = 18, so final price = 120 + 18 = 138 SAR. A common mistake is applying VAT before the discount or on the original price.
Question 3: What is the next number in the sequence: 2, 6, 18, 54, ___?
- 108
- 162 (Correct answer)
- 72
- 216
Correct answer: 162
Each number is multiplied by 3 to get the next: 2×3=6, 6×3=18, 18×3=54, 54×3=162.
This is a geometric sequence with a common ratio of 3. Each term is obtained by multiplying the previous term by 3: 2→6→18→54→162. To verify: 6/2=3, 18/6=3, 54/18=3. Therefore the next term is 54×3=162.
Question 4: If the average of five numbers is 24, and four of the numbers are 18, 22, 26, and 30, what is the fifth number?
- 20
- 24 (Correct answer)
- 28
- 22
Correct answer: 24
The sum of all five numbers = 24 × 5 = 120. The sum of the four known numbers = 18 + 22 + 26 + 30 = 96. The fifth number = 120 - 96 = 24.
Average = Sum ÷ Count, so Sum = Average × Count = 24 × 5 = 120. The four known numbers sum to 18 + 22 + 26 + 30 = 96. Therefore, the fifth number = 120 - 96 = 24. This is a standard GAT technique: use the average formula to find a missing value.
Question 5: A car travels 240 km in 3 hours. If it increases its speed by 20 km/h, how long will it take to travel 360 km?
- 3 hours
- 3.6 hours (Correct answer)
- 4 hours
- 4.5 hours
Correct answer: 3.6 hours
Original speed = 240/3 = 80 km/h. New speed = 80 + 20 = 100 km/h. Time = 360/100 = 3.6 hours.
Step 1: Original speed = distance ÷ time = 240 ÷ 3 = 80 km/h. Step 2: New speed = 80 + 20 = 100 km/h. Step 3: Time for new journey = distance ÷ speed = 360 ÷ 100 = 3.6 hours (or 3 hours and 36 minutes). This tests the fundamental relationship: speed = distance/time.
Question 6: What is 25% of 60% of 400?
- 40
- 60 (Correct answer)
- 80
- 100
Correct answer: 60
60% of 400 = 240. 25% of 240 = 60.
This is a chained percentage problem. First: 60% of 400 = 0.60 × 400 = 240. Then: 25% of 240 = 0.25 × 240 = 60. Alternatively, multiply the percentages: 0.25 × 0.60 = 0.15, then 0.15 × 400 = 60. Both methods give the same answer.
If 3x + 7 = 22, what is the value of 6x + 14?