So first what you want to do is take 98 and subtract it by 48. Which gives us 50. Now what we do is that since we are finding two numbers we would have to divide that by half, which would give us 25. Both of them are now equal. To find the number that makes that difference, we need to add 48 to one of the 25 values. Which would be 73. Meaning that the two numbers are 73 and 25. They both add up to 98 and 73 has a difference of 48 from 25.
Well the cost of the apples can be found by dividing the price by the amount bought. ($5/4 or $10/8 = $1.25/lb). If you want to find the amount for 6 pounds just multiply it by the individual cost (6x$1.25= $7.50)