JAMB Mathematics 2023 Paper

Concept:Use the relation: $\text{Speed} = \frac{\text{Distance}}{\text{Time}}$, so $\text{Time} = \frac{\text{Distance}}{\text{Speed}}$.Explanation:Let the distance between the two airports be $D$ km.Time to reach the airport = $\frac{D}{120}$ hours.Time to return = $\frac{D}{150}$ hours.Total flight time is given as 3 hours, so:$$\frac{D}{120} + \frac{D}{150} = 3$$The LCM of 120 and 150 is 600, so rewrite the fractions:$$\frac{5D}{600} + \frac{4D}{600} = 3$$$$\frac{9D}{600} = 3$$Simplify: $\frac{3D}{200} = 3$.Multiply both sides by 200:$$3D = 600$$$$D = 200 \text{ km}$$Answer:The distance between the two airports is $200$ km, which is option B.