Work out the percentage change when a price of £20 is increased to £50.

150%

Step-by-step explanation:

Let's say the 20 increased by x%. Then, we can write the equation:

20 + x% * 20 = 50

Notice that both terms on the left side have 20, so we can factor this out:

20 * (1 + x%) = 50

Divide both sides by 20:

1 + x% = 50/20 = 2.5

Subtract 1 from both sides:

x% = 1.5

Remember that % simply means "out of 100", so x% = x/100:

x/100 = 1.5

Multiply both sides by 100:

x = 150

Thus, the percent increase is 150%.

Hope this helps!