45 years
72 years
108 years
216 years
Correct answer is C
Given that the ages are in the ratio 3: 4: 5.
Let the sum of their ages be t.
\(\therefore\) The youngest age = \(\frac{3}{12} t\)
The eldest age = \(\frac{5}{12} t\)
\(\implies \frac{5}{12} t - \frac{3}{12} t = 18\)
\(\frac{2t}{12} = 18 \implies t = \frac{18 \times 12}{2}\)
t = 108 years.
The sum of their ages = 108 years.
If \(104_x = 68\), find the value of x
5
7
8
9
Correct answer is C
\(104_x = 68\\
1 \times x^2 + 0 \times x + 4 \times x^0 = 68\\
x^2 = 68 - 4; x^2 = 64\\
x = \sqrt{64}=8\)
Which of the following numbers is perfect cube?
350
504
950
1728
Correct answer is D
No explanation has been provided for this answer.
Simplify \(\left(\frac{16}{81}\right)^{-\frac{3}{4}}\times \sqrt{\frac{100}{81}}\)
\(\frac{80}{243}\)
\(\frac{1}{64}\)
\(\frac{25}{6}\)
\(\frac{15}{4}\)
Correct answer is D
\(\left(\frac{16}{81}\right)^{-\frac{3}{4}}\times \sqrt{\frac{100}{81}}\\
\frac{1}{\left(\sqrt[4]{\frac{16}{81}}\right)^3}\times \frac{10}{9}=\frac{1}{\left(\frac{2}{3}\right)^3}\times\frac{10}{9}\\
=\frac{27}{8}\times \frac{10}{9}=\frac{15}{4}\)
\(\frac{1}{3}\)
\(\frac{1}{2}\)
\(1\frac{1}{6}\)
\(1\frac{1}{2}\)
Correct answer is D
\(2\frac{1}{6} + 2\frac{7}{12}\)
= \(\frac{13}{6} + \frac{31}{12}\)
= \(\frac{26 + 31}{12}\)
= \(\frac{57}{12} = \frac{19}{4}\)
\(\frac{19}{4} - 3\frac{1}{4}\)
= \(\frac{19}{4} - \frac{13}{4}\)
= \(\frac{6}{4}\)
= \(1\frac{1}{2}\)