Fiza has 10 coins in a bag there are three £1 coins and seven are 50 pence coins
fiza takes at random, 3 coins from the bag
work out the probability that she takes exactly £2.50

The probability is 63/1000 or 0.063

Step-by-step explanation:

Here, given that she takes 3 coins , we want to calculate the probability that the sum is £2.50

What we simply have to do here is to get the different ways to arrange £2.50 within 3 selections ONLY

we can only have this as;

taking 2 £1 coins and 1 50 pence coins

The probability of taking a £1 coin is 3/10

The probability of taking a 50 pence coin is 7/10

So the probability of 2 £1 coins and 1 50 pence coins will be;

3/10 * 3/10 * 7/10 = 63/1000

x= -3 and

step-by-step explanation:

to find the roots of a cubic, use division or factoring to find the factors then set equal to 0. as this is a difference of cubes, it factors into

where a is the cube root of .

here   this is 27 and the cube root of 27 is 3. so we write using the form:

.

set each factor to 0 and solve for x.

x-3=0

x=3

the quadratic expression does not factor and must be solved using the quadratic formula.

where a = 1, b=3, and c=9

this cubic has two complex roots.