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Talil is going to make some concrete mix. He needs to mix cement, sand and gravel (1: 3:5) by weight. Talil wants to make 180 kg of concrete mix. He has 15 kg of cement, 85 kg of sand, 100 kg of gravel. Does he have enough to make the concrete?

In order to answer this question you need to find out how much cement, sand and gravel is needed to make 180kg of concrete mix. To do this you must find out how many parts the concrete mix ratio is made up (...
KM
Answered by Katie M. • Maths tutor
34417 Views

The point A lies on the curve with equation y = x^(1/2). The tangent to this curve at A is parallel to the line 3y-2x=1. Find an equation of this tangent at A. (PP JUNE 2015 AQA)  

My exact explanation would depend on the students level of understanding. The following answer assumes a basic understanding of differentiation and equations of lines; a) Gradient of tangent is equal to grad...
SC
Answered by Sefret C. • Maths tutor
7971 Views

John has 12 marbles. Sandra has 10 more marbles than Kathy. Kathy has 4 times as many marbles as John. How many marbles does Sandra have?

This question asks how students can formulate linear equations from worded questions. The first step is to give each person an algabraic symbol. j for John, s for Sandra and k for Kathy works fine. Next, stu...
JW
Answered by James W. • Maths tutor
5618 Views

How do you differentiate x^x?

To differentiate x x , we first let y = x x . ( Note that x x is not in the form x c where c is a constant or a x where a is a constant so the usual differentiation formulas cannot be used ). The trick here ...
AP
Answered by Anish P. • Maths tutor
3807 Views

The straight line with equation y = 3x – 7 does not cross or touch the curve with equation y = 2px^2 – 6px + 4p, where p is a constant. Show that 4p^2 – 20p + 9 < 0.

The main piece of information this question gives us is that the two lines do not cross or touch. From this we can immediately see that we will need to use the discriminant of the quadratic formula b 2 - 4ac...
MW
Answered by Molly W. • Maths tutor
27711 Views