Let x litre water is added to 45% solution of acid. (i) 25 % of (1125 + x) < $\frac{1125 \times 45}{100}$ or $\frac{1125+x}{4}$ < $\frac{1125 \times 9}{20}$ ⇒ 5(1125 + x) < 10125 ⇒ 5625 + 5x < 10125 ⇒ 5x < 10125 – 5625 or x < $\frac{4500}{5}$ = 900 ... (i) (ii) Further, 30% of (1125 + x) > $\frac{1125 \times 45}{100}$ or $\frac{3}{100}$ × (1125 + x) > $\frac{1125 \times 45}{100}$ > $\frac{1125 \times 9}{20}$ ⇒ 6(1125 + x) > 1125 × 9 ⇒ 6750 + 6x > 10125 ⇒ 6x > 10125 – 6750 ⇒ 6x > 3375 or x > $\frac{3375}{6}$ = 562.5 ... (2) From (1) and (2), we have 562.5 < x < 900