Two bonds are identical, except one has a yield to maturity of $4\%$ while the other has a yield to maturity of $13\%.$ If the bonds don't default and if interest rates remain the same, you could earn higher returns with the $4\%$ bond

The yield to maturity of a long term bond is very difficult to calculate by hand, the only practical way to compute it is with a calculator

If you pay less for a bond, the yield to maturity of the bond increases Yield to maturity is defined as the ratio between the coupon payment divided by the price of the bond