If $${a+b=10}$$ and $$ \sqrt{a\over b}-13=-\sqrt{b\over a}-11$$, then what is the value of $${3ab+4a^2+5b^2}$$?

If $$ {3\sqrt{{1-a}\over{a}}}+9={19-3\sqrt{{a}\over{1-a}}}$$, then what is the value of a?

By what least number should 4320 be multiplied so as to obtain a number which is perfect cube? 

A tourist spends daily as many rupees as the number of days of his total tour. If his total expenses were ₹ 361, then how many days did his tour last? 

Find the value of $$ (2 {1\over6}+1 {13\over18}-{1\over6}) × {16÷4}$$

The value of x in the given equation
$$ {23 ^2 + \sqrt{x}=625}$$

(0.04)^-1.5 on simplification gives: 

Given that ( 1² +2²+3²+………..+10²)=385, the value of (2²+4²+6²+……20²) is equal to