50% probability is there for a child to have widows peak and dimples if its parents are heterozygous for both traits.
Explanation:
Widows peak is a dominant trait on straight hair line.
Dimples are dominant traits over non dimples.
It is given that parents are heterozygous for the trait. So genotype of parents will be
WwDd X WwDd
The punnet square shows:
The gametes will be WD, wd, Wd,wD
WD Wd wD wd
WD WWDD WWDd WwDD WwDd
Wd WWDd WWdd WwDd Wwdd
wD WwDD Wwdd wwDD wwDd
wd WwDd Wwdd wwDd wwdd
8 progeny Will have both widow's peak and dimples. The results of the cross shows that there is 50% probability that the progeny will have both the traits when parents are heterozygous.