Solution:Let the number of seats for class 9th, 10th and 11th respectively = 8x, 10x, 12x Number of increase seats for class 9th, 10th and 11th respectively ⇒ (130% of 8x), (140% of 10x) and (150% of 12x)
⇒ (130/100 × 8x), (140/100 × 10x) and (150/100 × 12x)
⇒ (52x/5), (14x) and (18x)
Required ratio,
⇒ 52x/5 : 14x : 18x
⇒ 52x : 70x : 90x
⇒ 26 : 35 : 45
∴ The ratio of increased seats is 26 : 35 : 45.