90.69 rounded to the nearest tenth. Go to the tenth value of the number and look to the number right of that. If it is 5 or higher, you round up; 4 or less, round down 9 is higher than 5 therefore you round up 90.69 becomes 90.7
If A is equal to 30, and A+B equals 42. That means B equals 12. So, if the value increased with the same rate of change, it would be 54. This is because 30 plus 12 is 42. 42 plus 12 would equal 54.
