The sum of three numbers is 98. If the ratio of the first to the second is 2:3 and that of the second to the third is 5:8. then the second number is
1). 49
2). 48
3). 30
4). 20
Let the numbers be x, y and
z. Then
x : y = 2 : 3 ; y : z = 5 : 8
$\therefore$ x : y : z = 2 × 5 : 3 × 5 : 3 × 8
= 10 : 15 : 24
Sum of the ratios
= 10 + 15 + 24 = 49
$\therefore$ The second number,
$\frac{15}{49}\times98$=30
2. The third proportional of two numbers 4 and 28 is _______.