If masses of two point objects is doubled and distance between them is tripled, then gravitational force of attraction between them will nearly

Solution :
$$\eqalign{ & \% \,{\text{change}} = \frac{{\left[ {\frac{{G\left( {2{m_1}} \right)\left( {2{m_2}} \right)}}{{{{\left( {3r} \right)}^2}}} - \frac{{G{m_1}{m_2}}}{{{r^2}}}} \right]}}{{\frac{{G{m_1}{m_2}}}{{{r^2}}}}} \times 100 \cr & = \frac{{\frac{4}{9} - 1}}{1} \times 100 \cr & = - 56\% , \cr} $$
$$-ve$$  sign indicates that force of attraction decreases.