1. The family consists of four people. If Martha's scholarship is doubled, the family's total income will increase by $5 \%$; if Mom's salary is doubled, the total income will increase by $15 \%$; if Dad's salary is doubled, the total income will increase by $25 \%$. What percentage will the family's total income increase if Grandpa's pension is doubled?
If each person's income doubles, the total family income will increase by $100 \%$. Of this $100 \%$, $5 \%$ belongs to Martha, $15 \%$ belongs to Mom, $25 \%$ belongs to Dad, and the remaining $55 \%$ is contributed by Grandpa.