Тато збирає в саду за 1 год 7 ящиків яблук, а син за 1 год — на 3 ящики менше. Скільки ящиків яблук збирають тато й син разом за 3 год?

San Francisco , under the influence of the California Mediterranean climate, characterized by mild wet winters and warm dry summers. San Francisco is surrounded on 3 sides by water, so the climate is strongly influenced cool currents of the Pacific ocean, which produce mild climate with little seasonal temperature fluctuations. The average summer temperature is 21 C, which on 9 degrees C lower than in Livermore, the nearest town within the continent.