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Why is my answer incorrect?

Check for any silly mistakes, a lost negative or a simple arithmetic error. If you can’t find any, we’ll work through the question together and see where the method differs from yours. Then we will work out ...
ZG
Answered by Zachary G. • Maths tutor
3322 Views

There are 9 counters in a bag. 7 of the counters are green. 2 of the counters are blue. Ria takes at random two counters from the bag. Work out the probability that Ria takes one counter of each colour. You must show your working.

Probability that Ria takes Green then Blue is 7/9 * 2/8 = 14/72. Probability that Ria takes Blue then Green is 2/9 * 7/8 = 14/72. Added together we get 28/72 = 7/18.
ZG
Answered by Zachary G. • Maths tutor
14440 Views

Why does Benzene require a catalyst to react with Bromine whereas Phenol does not?

The -OH is an activating group, it donates its lone pair into the delocalised ring of electrons. This increases the electron density in the ring, making it more reactive.
FL
Answered by Frankie L. • Chemistry tutor
2747 Views

If 3x^2 = 48 find x

3x^2 = 48 x^2 = 16 x = 4
FL
Answered by Frankie L. • Maths tutor
3083 Views

The equation 3x^2 – 5x + 4 = 0 has roots P and Q, find a quadratic equation with the roots (P + 1/2Q) and (Q + 1/2P)

We know the roots of the equation 3x 2 - 5x + 4 = 0 is P & Q, therefore is is equivalent to (x - P)(x - Q) = 0. Expanding the expression we get x 2 - x(P+Q) + PQ = 0 . Equating coefficents with the origi...
SC
3785 Views