Question

Here are five number cards 2, 5, 7, 8,9. One of the cards is removed and the mean average of the remaining four number cards is 6. Which card was removed you must show your working out

Answer 1

7

Step-by-step explanation: Trust me

Answer 2

Calculate the average of the five original cards:

2+5+7+8+9=31

31/5 = 6.2

So, if a card was removed, the four remaining cards would have an average of 6, meaning that they would add up to 24.

31-x=24?

Subtract 31 from both sides: -x=-7

Divide by -1 on both sides: x=7

So, we know that 7 was removed.

Let me know if this helps!