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There are n sweets in a bag, 6 of which are red. The rest of the sweets are blue. Jen removes 1 sweet from the bag. Jen then takes another sweet from the bag. The probability that Hannah takes two red sweets is 1/3. Show that n²-n-90=0.

We know the total number of sweets is n, and that 6 are red. When Jen takes the first sweet, the probability of it being red is [number of red sweets] / [how many there are] = 6/n . For the second sweet, ...

Answered by Amy B. • Maths tutor

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Lewis wins £360 in a prize draw. He gives 15% to charity and puts 3/8 into his savings. The rest he uses to buy a bike. How much of the money has Lewis got left for this bike? Note: do not use a calculator

10% of £360 is £36. Therefore 5% of £360 would be £18 (half of the 10% figure). Added together, 15% of £360 would be £54. 1/8 of £360 is £45 (half £360 three times), therefore 3/8 would be £135 (£45*3). £...

Answered by Lewis B. • Maths tutor

3253 Views

how do I differentiate?

look at the power of term and multiply the coefficient of that term by the value of the power, then reduce the value of the terms power by 1. for example after differentiation 5X⁴becomes 20X

Answered by Stefen L. • Maths tutor

3103 Views

y = (x^2)sin(3x). Find dy/dx

We need to differentiate x²sin(3x). We know how to differentiate (x²) on its own, and how to differentiate sin(3x) on its own. So we can use the Product rule:

dy/dx = (d/dx(x<...

Answered by Robert D. • Maths tutor

18392 Views