1. Qutida qizil, ko‘k va yashil rangli tugmalar bor. Qizil tugmalar sonining ko‘k tugmalar soniga nisbati 4 : 1. Qizil tugmalar sonining yashil tugmalar soniga nisbati esa 3 : 2. Qizil tugmalar yashil tugmalardan 120 taga ko‘p ekani ma’lum. a) Ko‘k, qizil va yashil tugmalar sonining nisbatini toping. b) Qutida jami nechta tugma bor?

Qizil, ko‘k va yashil tugmalar sonini mos ravishda Q, K va Y deb belgilaymiz.

1. Qizil va yashil tugmalar nisbati 3 : 2 bo‘lgani uchun Q − Y qizil tugmalar sonining 1/3 qismiga teng. Bu farq 120 ta:

   Q ÷ 3 = 120, demak Q = 360.

2. Qizil va ko‘k tugmalar nisbati 4 : 1: 360 ÷ 4 = 90 ta ko‘k tugma.

3. Qizil va yashil tugmalar nisbati 3 : 2: 360 ÷ 3 × 2 = 240 ta yashil tugma.

4. a) Ko‘k, qizil va yashil tugmalar nisbati 90 : 360 : 240. Nisbatni 30 ga qisqartiramiz: 3 : 12 : 8.

5. b) Jami tugmalar: 90 + 360 + 240 = 690.