Complex sentence: A survey of 80 American women showed that 30% were motivated by altruism alone, another 20% were attracted only by monetary compensation, while 40% of donors were motivated by both reasons.
Split into simpler sentences: A survey of 80 American women showed that 30% were motivated by altruism alone. Others, 20%, were attracted only by monetary compensation, while 40% of donors were motivated by both reasons.