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x : y = 7 : 4, x + y =88. Work out the value of x - y.

Here we use the ratios given to calculate the answer. First we sum add 7 and 4 to find total parts. 7 + 4 = 11. Then we divide 88 by 11. 88/11 = 8.This means we know that each part in the given ratio is 8...

Answered by Alice C. • Maths tutor

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Eleven pet owners were asked how many pets they had in total. The results are given below. 1, 1, 2, 3, 4, 5, 5, 6, 6, 6, 7 - Two more owners are asked how many pets they have. Including their results the mean goes down to 4 but the mode is unchanged from

1, 1, 2, 3, 4, 5, 5, 6, 6, 6, 7 - n=11mean = 46/11mode= most common so 6after n=13, mean is 413*4=52so 52-46=64 and 2 works1 and 5 not as mode changes3 and 3 not as mode changes

Answered by Rishi J. • Maths tutor

1432 Views

Find the two real roots of the equation x^4 -5=4x^2 Give the roots in an exact form.

Disguised quadratic. Let y=x^2So quadratic become y^2-4y-5=0so (y-5)(y+1)=0so y=5 and y=-1so x^2 = 5 or -1cannot be -1 as not real henso x^2=5x=+-sqrt(5)

Answered by Rishi J. • Maths tutor

3073 Views

The straight line L1 passes through the points with coordinates (4, 6) and (12, 2) The straight line L2 passes through the origin and has gradient -3. The lines L1 and L2 intersect at point P. Find the coordinates of P.

Find equation of line 1 in terms of x. eg y=mx+c - Using gradient and points. Equation of line 2 is just y=-3xSo -3x=mx+c of line 1Find xSub into one equation to find the y point.Done

Answered by Rishi J. • Maths tutor

9200 Views

A ball, dropped vertically, falls d metres in t seconds. d is directly proportional to the square of t. The ball drops 45 metres in the first 3 seconds. How many metres does the ball drop in the next 7 seconds?

d = kt². 45 = k x 3². 45 = k x 9 (/9). 5 = k.3+7 = 10 seconds total as we are investigating the NEXT 7 seconds. d = kt². d = 5 x 10². d = 5 x 100d = 500m in 10 ...

Answered by Emily N. • Maths tutor

3730 Views