Which of the following statements is true for the relationship between reliability and validity of a research tool ?

A valid test must be reliable.

• In an alloy, zinc and copper are in the ratio 1 : 2. In the second alloy, the same elements are in the ratio 2 : 3. If these two alloys be mixed to form a new alloy in which two elements are in the ratio 5:8, the ratio of these two alloys in the new allow
• Direction: Read the following information carefully and answer the questions that follow: P, V, X, A, D, I, K and U set out for trip for different number of days such as 2, 8, 11, 5, 6, 4, 7 and 3, they go to the trip in the same order but the order of n
• X and Y are two alloys which are prepared by mixing zinc and aluminium in the ratio of 1 : 4 and 11 : 8 respectively. If equal quantities of alloys are melted to form a third alloy Z then what is the ratio of zinc and aluminium in alloy Z?
• The total number of students in a school was 660. The ratio between boys and girls was 13:9. After some days, 30 girls joined the school and some boys left the school and new ratio between boys and girls became 6: 5. The number of boys who left the school
• The distance between two places, A and B, is 300 km. Two riders, on scooters start simultaneously from A and B towards each other. The distance between them after 2.5 hrs is 25 km. If the speed of one scooter of one scooter is 10 km/hr more than the other