Entrance Exams
Govt. Exams
Combined rate = 1/10 + 1/15 = 5/30 = 1/6. Time = 6 hours
Original speed = 120/8 = 15 km/h. New speed = 15 × 1.25 = 18.75 km/h. Distance in 5 hours = 18.75 × 5 = 93.75 km
SP = MP × (100-discount%)/100 = CP × 1.4 × 0.8 = 1.12CP. Profit% = 12%
Let the two-digit number be AB (value = 10A + B). The four-digit number ABAB = 1000A + 100B + 10A + B = 1010A + 101B = 101(10A + B) = 101 × AB. Also, ABAB = 1100A + 11B = 11(100A + B). So it's always divisible by both 11 and 101.
Let three consecutive integers be n, n+1, n+2. Sum: n + (n+1) + (n+2) = 54, so 3n + 3 = 54, 3n = 51, n = 17. The smallest number is 17. Required result: 3(17) + 5 = 51 + 5 = 56.
Let the two consecutive odd numbers be (2n-1) and (2n+1). Their product: (2n-1)(2n+1) = 483. This gives 4n² - 1 = 483, so 4n² = 484, n² = 121, n = 11. The numbers are 21 and 23. Sum = 21 + 23 = 44.
Using exponent rules: (2⁵ × 3⁴)/(2³ × 3²) = 2^(5-3) × 3^(4-2) = 2² × 3² = 4 × 9 = 36.
Check sum of digits: 121: 1+2+1 = 4 (not divisible by 3), 122: 1+2+2 = 5 (not divisible by 3), 123: 1+2+3 = 6 (divisible by 3) ✓, 124: 1+2+4 = 7 (not divisible by 3). Therefore 123 is divisible by 3.
Use the formula: HCF × LCM = Product of two numbers. So 4 × 48 = 16 × other number. Therefore 192 = 16 × other number, which gives other number = 192/16 = 12.
Prime factorization: 48 = 2⁴ × 3, 64 = 2⁶, 80 = 2⁴ × 5. HCF is the product of lowest powers of common prime factors. Only 2 is common to all. Lowest power of 2 is 2⁴ = 16. Therefore, HCF = 16.