The difference between the ages of mother and son was 21 when mother's age was 43. If father is elder by 3 years to mother, what will be the difference between the ages of son and father when father attains 50 years?
In ΔPQR, S and T are points on side PQ and PR respectively. ST is parallel to QR. If S divides PQ in the ratio 4:3 and length of QR is 4.9 cm, find ST?