Let, the length be l and breadth be b.
So, 2(l + b) = 26
Or, l + b = 13
Or, l = 13 - b
So, we may write like this,
Area = l * b
Or, l * b > 30
Or, l (13 - l) > 30
Or, 13l - l^2 > 30
Or, l^2 - 13l + 30 > 0
Or, l^2 - 3l - 10l + 30 > 0
Or, l(l - 3) - 10(l - 3) > 0
Or, (l - 3)(l - 7) > 0
Or, l - 7 > 0
Or, l > 7.
Now, putting the value of l,
We get, l * b > 30
Or, 7 * b > 30
Or, b > 30/7
➡️ Therefore, we get,
Length > 7
Breadth > 30/7
That's it..
Here we can solve this question using<em> </em><em>Unitary</em><em> </em><em>Method</em><em> </em><em>.</em> As ;
→ In 17hrs the boat travels 452km
→ In 1hr the boat will travel 452km/17
→ In 9hrs the boat will travel 452/17km * 9 = 239.29km
→ A car can travel 156km on 13L gasoline .
→ It will travel 1km on 13/156L of gasoline .
→ It will travel 480km on 13/156*480L = 40L of gasoline .
→ A boat can go 180 miles on 60L gasoline.
→ It will go 1mile in 60/180L of gasoline.
→ It will go 306 miles in 60/180*306L = 102L of gasoline .
→ On 51L of gasoline a car can go 408km
→ On 1L of gasoline car will go 408/51 km
→ On 11L of gasoline it will go 408/51*11L = 88km
