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The mass of a substance is increasing exponentially. Initially its mass is 37.5g, 5 months later its mass is 52g. What is its mass 9 months after the initial value to 2 d.p?

M=37.5e kt 52=37.5e k 5 52/37.5=e 5k ln(52/37.5)=5k (1/5) (ln(52/37.5))=k k≈0.06538 when t=9, M=37.5e 9*0.06538 M=67.54
RR
Answered by Riccardo R. • Maths tutor
4678 Views

At a school number of boys : number of girls = 9 : 7 There are 116 more boys than girls. Work out the total number of students at the school.

B:G --> 9:7 Expressed as fractions of the whole group, boys are 9/16 of the group and girls are 7/16 of the group. We can use algebra to work out the total group number. For our working, I will use x to r...
DM
Answered by Dionne M. • Maths tutor
16547 Views

What is the integral of x^(3)e^(x) with respect to x?

This question is looking at integration by parts. Therefore, we need to split the integral into two parts. Part A will be x 3 and Part B will be e x . Draw 2 columns putting Part A in the RIGHT and B in the ...
JB
Answered by James B. • Maths tutor
5436 Views

How do I break down (x-2)/((x+1)(x-1)^2) into partial fractions?

Firstly, let (x-2)/((x +1)(x-1) 2 ) = A/(x+1) + B/(x-1)+C/(x-1) 2 , where A,B and C are to be calculated. Then, multiply both sides of the equation by (x+1)(x-1) 2 which will leave an equation as follows; x-...
DO
Answered by Daniel O. • Maths tutor
4489 Views

White paint costs £2.80 per litre. Blue paint costs £3.50 per litre. White paint and blue paint are mixed in the ratio 3 : 2. Work out the cost of 18 litres of the mixture.

The ratio given tells us that our paint mixture of 18 litres consists of 3 + 2 = 5 parts . Each part therefore consists of 18/5 = 3.6 litres of paint . If we need 3 parts white paint, thats: 3 (parts) x 2.80...
VO
Answered by Vicente O. • Maths tutor
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