Question
In a group of three numbers first is double of second
and half of third. The average of three numbers is 42. Find the difference between the first number and third number?Solution
Let the first number be ‘x’ Second number = x/2 Third number = 2x According to the question, (x+x/2+2x)/3 = 42 (2x+x+4x)/6 = 42 7x = 42 × 6 x = 36 ∴ Required difference = 72 - 36 = 36
Choose the number which is different from the group.
 How many numbers up to 800 are divisible by both 3 and 5?
15Â Â Â Â Â Â Â Â Â Â 15Â Â Â Â Â Â Â Â Â Â 60Â Â Â Â Â Â Â Â Â Â 540Â Â Â Â Â Â Â Â 8650
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