Class 61 is planning to use the red scarf fund to buy some stationery to give to peers in the orphanage. With this money, they can buy 50 stationery boxes alone and 30 pens alone.

The unit price ratio of pencil cases and pens is (3:5).

The radius of the large circle is 3 cm, and the radius of the small circle is 1 cm. The simplest integer ratio of the areas of the large circle and the small circle is (9:1).

In a ratio, two external terms are reciprocals of each other. One of the internal terms is 0.25, and the other internal term is (1÷0.25=4).

0 20 40 kilometers, this is (scale), it means that 1 centimeter on the map is equivalent to the actual distance |————|————| (20) kilometers, changing it into a numerical scale is (1:2000000

).

If 6a=5b (b is not equal to 0), then a:b=(5):(6); if m:three-quarters=8:eighth, then m=(48).

The length of a bridge model is 26 centimeters. The ratio of the model length to the actual length of the bridge is 1:1500. The actual length of the bridge is (390) meters.

The sugar content of a kind of sugar water is 5%.

The simplest integer ratio of sugar to water in this kind of sugar water is (5:95=1:19).