Jar P has milk and water in the ratio $5 : 3$ , and jar Q has them in the ratio $7 : 1$ . In what ratio should the contents of P and Q be mixed to get milk and water in the ratio $2 : 1$ ?

1 : 5

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1 : 1

Correct answerYour answer

5 : 1

Correct answerYour answer

2 : 1

Correct answerYour answer

Show the answer and explanation

CorrectNot quiteAnswer C

Correct answer: C

Milk fractions: P = $\frac{5}{8}$ , Q = $\frac{7}{8}$ , target = $\frac{2}{3}$ .
$P : Q = \left(\frac{7}{8} - \frac{2}{3}\right) : \left(\frac{2}{3} - \frac{5}{8}\right) = \frac{5}{24} : \frac{1}{24}$ .
= $5 : 1$ .

Worth noting

Write every mixture as the fraction of milk in the WHOLE before applying alligation. $1 : 5$ is the reversed ratio; the target $2/3$ is much nearer P's $5/8$ .

Concept: Combining two mixtures to reach a target ratio
Typical timeTypical: 90 s
Your timeYours: —

The rule this testsMixtures and replacement

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Ten questions from Mixtures & Alligation, at your own pace.

Jar P has milk and water in the ratio 5:35 : 35:3, and jar Q has them in the ratio 7:17 : 17:1. In what ratio should the contents of P and Q be mixed to get milk and water in the ratio 2:12 : 12:1?

Explanation

Jar P has milk and water in the ratio $5 : 3$ , and jar Q has them in the ratio $7 : 1$ . In what ratio should the contents of P and Q be mixed to get milk and water in the ratio $2 : 1$ ?