Question : Water has maximum density at

Option 1: 100^oC

Option 2: 0^oC

Option 3: 4^oC

Option 4: 273^oC

Question : The average age of 14 friends is 14 years. If the age of $15^{\text {th }}$ friend is added, then the average remains the same. What is the age of the $15^{\text {th }}$ friend?

Option 1: 15 years

Option 2: 18 years

Option 3: 14 years

Option 4: 12 years

Question : If (a + b + c) = 7 and ab + bc + ca = 12, find the value of a² + b² + c².

Option 1: 29

Option 2: 31

Option 3: 27

Option 4: 25

Question : The average age of 30 students in a class is 12 years. The average age of a group of 5 of the students is 10 years and that of another group of 5 of them is 14 years. The average of the remaining students is:

Option 1: 14 years

Option 2: 12 years

Option 3: 11 years

Option 4: 13 years

Question : If a + b + c = 0, then the value of (a + b – c)² + ( b + c – a)² + ( c + a – b)² is:

Option 1: 0

Option 2: 8abc

Option 3: 4(a² + b² + c²)

Option 4: 4(ab + bc + ca)