Quadratic equations word problems (intermediate)

Paritosh took a trip on a boat that took him $10$10 hours. He travelled $30\,\text{km}$30, start text, k, m, end text upstream and $44\,\text{km}$44, start text, k, m, end text downstream to reach his destination.

The constant speed of the stream is $3\,\dfrac{\text{km}}{\text{hr}}$3, start fraction, start text, k, m, end text, divided by, start text, h, r, end text, end fraction.

Let $b\,\dfrac{\text{km}}{\text{hr}}$b, start fraction, start text, k, m, end text, divided by, start text, h, r, end text, end fraction be the constant speed of the boat in still water.