Tony buys 12 apples and 7 pears for £10.90. An apple costs 20p less than a pear. What would be the cost of 4 apple and 9 pears?

Let's call an apple 'a', and a pear 'p'.If Tony bought 12 apples and 7 pears for £10.90, then we can write the following equation:12a + 7p = 10.9If an apple costs 20p less than a pear, we can say:a = p - 0.2Treating these as simultaneous equations, we can use the second equation to replace 'a' in the first equation with 'p - 0.2':12(p - 0.2) + 7p = 10.9This can be simplified:12p - 2.4 + 7p = 10.919p = 13.3p = 0.7Putting this value back into the second equation, we get:a = 0.7 - 0.2which simplifies to:a = 0.5So, an apple costs 50p and a pear costs 70p.Now, to find the cost of 4 apples and 9 pears:4 x 0.5 + 9 x 0.7 = 8.3So the cost is £8.30.