hi there....well im only 13 and my bp is usually 113 over 72 and pulse is 75 bpm. in your bp, the bottom number is very low, but im no expert. it could have had something to do with when your bp was taken. it also just could have been a mistake because i highly doubt the top would be 115 and the bottom 42...go check it out again at a different time,see what happens,and if you are worried,check in with your doctor.
I should of also posted that I am 50 years old, I weigh 200 lbs , work in a factory and do go to walks almost daily. That gives a bit more background that could help in any advice.
Thank you