Top answers

The average age of a group of 6 people is 21. One more person joins the group and the average is now 25. How old is the new member of the group?

To work out averages we add up all of the ages and divide by the number of people in the group. So that means in the first group, before the new person joined in, all the ages added up and divided by 6 equal...
AK
Answered by Alok K. • Maths tutor
32555 Views

Differentiate f(x) = 3x^2+5x+3

Remember the rules for differentiation? We take each term which looks like ax n where a and n are just numbers and we turn it into: (an)x n-1 So for this example, we go term by term and get: f'(x) = 6x 2 + 5...
AK
Answered by Alok K. • Maths tutor
4999 Views

The quadratic equation 2x^2-8x+1 = 0 has roots a and b. Find the value of a + b and ab

There is no need to solve the quadratic equation here. Use the formulae for the sum and product of roots where: a+b = -b/a and ab = c/a Therefore in this instance: a+b = -(-8)/2 = 4 and ab = 1/2
AK
Answered by Alok K. • Maths tutor
9540 Views

If (2x+3)/(x-4)-(2x-8)/(2x+1)=1, what is x?

First eliminate fractions; Multiplying both sides by (x-4) gives; (2x+3)-((2x-8)(x-4))/(2x+1)=(x-4) Multiplying both sides by (2x+1) gives; (2x+3)(2x+1)-(2x-8)(x-4)=(x-4)(2x+1) Now simplify the expression; E...
HC
Answered by Hannah C. • Maths tutor
3382 Views

The shortest side of a triangle is 4.3m long. Two of the angles are 45.1 and 51.2 degrees respectively. Find the length of the longest side.

To begin we calculate the third unknown angle in the triangle by taking the two known angles (45.1 and 51.2) away from 180 degrees (remember the interior angles of a triangle sum to 180). We find this angle ...
AJ
Answered by Adam J. • Maths tutor
6070 Views